: 

s 


MOTOR    BOATS 
HYDROPLANES 

HYDROAEROPLANES 

Construction  and  Operation  with  Practical 
Notes  on  Propeller  Calculation  and  Design 

An  Illustrated  Manual  of  Self  Instruction  for 
Owners  and  Operators  of  Marine 
Gasoline  Engines  and  Ama- 
teur Boat-Builders 
E 

i 

THOMAS  H.  RUSSELL,  A.  M,  M.  E. 

With 

Revisions  and  Extensions 

By 
JOHN  B.  RATHBUN,  M.  E., 

Consulting  Engineer  and  ui-mictor  Chicago  Technical  College 


1917 

CHARLES  C.  THOMPSON  CO. 
CHICAGO.  U.  S.  A. 


- 


COPYRIGHT,  1917 

BY  CHARLES  C.  THOMPSON  CO. 
CHICAGO 


MOTOR  BOATS 

Copyright  MCMX 

By  Charles  C.  Thompson  Co. 

(Not  Inc.) 

Copyright  MCMXII 

By  CHARLES  C.   THOMPSON  CO. 


PREFACE. 

The  purpose  of  this  work  is  to  provide  a  compendious 
guide  to  the  design,  construction,  installation  and  opera- 
tion of  marine  motors  and  to  the  design  and  construction 
of  motor  boats.  It  will  be  found  useful  and  often  in- 
valuable, alike  by  the  man  who  wishes  to  install  a  small 
motor  in  his  rowboat  or  yacht,  and  his  more  ambitious  or 
more  fortunate  brother  who  aspires  to  own  a  seagoing 
power  craft.  It  is  intended  primarily  for  the  man  who 
is  not  a  practical  mechanic — and  yet  mechanics  may 
study  its  pages  with  profit. 

Boat-building  has  ever  been  a  favorite  avocation  among 
the  people  of  maritime  nations.  In  the  United  States  and 
Canada,  blessed  as  they  are  with  countless  navigable 
lakes  and  rivers  as  well  as  a  splendid  seaboard,  the  build- 
ing and  operation  of  pleasure  boats  is  a  national  pastime, 
which  has  been  stimulated  by  the  development  of  the 
marine  gasolene  engine,  so  that  today,  while  thousands 
of  small  craft  are  turned  out  annually  by  the  profes- 
sional boat-builders,  amateur  boat-building  has  vastly  in- 
creased. To  those  who  are  building  or  who  wish  to 
build  their  own  craft,  the  present  work  offers  a  valuable 
guide. 

As  far  as  the  installation  and  operation  of  marine  en- 
gines are  concerned,  it  is  estimated  by  manufacturers  of 
world-wide  renown  that  fully  eighty  per  cent  of  their 
engines  are  used  by  people  who  have  little  or  no  "motor 
knowledge."  Few  persons  have  an  opportunity  to  ope- 
rate a  motor  before  they  own  one,  hence  the  great  ma- 
jority of  boat  engines  are  sold  to  the  inexperienced. 

In  the  confident  belief  that  most  of  these  purchasers 
and  users  of  marine  engines  would  prefer  to  have  at  least 
a  working  knowledge  of  motor  construction  and  opera- 


4  MOTOR  BOATS: 

tion,  this  book  covers  the  subject  thoroughly.  It  exploits 
no  unproved  theories,  but  embodies  only  facts  and  prin- 
ciples of  construction  which  are  recognized  and  accepted 
by  the  foremost  builders  of  motor  boats  and  marine  en- 
gines. It  does  not  profess  to  describe  every  good  engine 
on  the  market,  but  does  describe  to  the  last  detail  those 
which  are  typical  of  the  best  and  most  advanced  construc- 
tion. It  appeals,  therefore,  to  all  present  and  prospective 
owners  of  motor  boats  who  wish  to  learn  how  to  operate 
their  craft  to  the  best  advantage. 

Probably  one  of  the  most  important  chapters  is  that 
which  treats  of  the  elementary  theory  and  construction 
of  the  propeller.  This  subject  is  treated  as  fully  as 
possible  in  a  book  of  this  scope  and  many  useful  hints 
are  given  regarding  the  selection  of  a  propeller.  The 
design  of  a  propeller  is  a  highly  technical  subject,  but 
with  the  data  given,  the  amateur  has  at  least  a  guide  by 
which  to  work. 

Hydroplanes  and  hydroaeroplanes,  the  latest  develop- 
ment in  water  craft  are  each  given  a  chapter.  The  con- 
struction of  the  hulls,  and  the  principle  of  sustenation 
by  reaction  are  fully  explained  in  a  simple  manner  and 
are  clearly  illustrated. 


CONTENTS 

Chapter.  Page. 

I.  The  Modern  Motor  Boat 7 

Ideal  Power  for  Small  Self-Propelled 
Craft — Development  of  the  Gasoline 
Motor  —  Amateur  Boat  Building — 
Choosing  an  Engine,  Etc. 

II.  Marine  Gasoline  Engines — 1.     The  Four- 

cycle Type 13 

III.  Marine   Gasoline   Engines — 2.     The  Two- 

cycle  Type 20 

IV.  Carburation  and  Carbureters 30 

The  Float-feed  Principle — The  Mixing 
Valve  or  Vaporizer — Spray  Carbu- 
reters—The Puddle  Type,  Etc. 

V.  Ignition    37 

Various  Methods — Dry  Cells — Wet  Bat- 
teries— Magneto  Ignition — Make  and 
Break  and  Jump  Spark  Systems — In- 
stallation— Wiring,  Etc. 

VI.  Lubrication  and  Cooling  Systems 61 

The  Best  Lubricants— The  Splash  Sys- 
tem— Mechanical  Oilers,  Etc. — Air  and 
Water  Cooling  Methods. 

VII.  Exhaust  Devices  70 

Air  and  Water  Mufflers— The  Under- 
water Exhaust,  Etc. 


CONTENTS— Continued. 

Chapter.  Page. 

VIII.  Installation  of  Motor  Boat  Engines 75 

IX.  Operation  and  Care  of  Engine 91 

X.  Hydroplanes    97 

XL  Choice  of  a  Boat  Model 107 

XII.  Practical  Boatbuilding — 1.     Boat  Patterns 

and  Knock-down  Frames 125 

XIII.  Practical     Boatbuilding  —  2.       Form     and 

Strength  of  Hull 137 

XIV.  Practical      Boatbuilding  —  3.        Structural 

Members  and  Materials 143 

XV.  Practical  Boatbuilding — 4.     Laying  Down 

and  Assembling — Finishing   151 

XVI.  Practical  Boatbuilding — 5.     How  to  Build 

a  Boat  from  Patterns. 165 

XVII.  Propellers — Theory  and  Construction 192 

XVIII.  Reversing- Gear  and  Propeller  Wheels. ...  211 

XIX.  Hydroaeroplanes    217 

XX.  Engine  Troubles  and  Their  Remedies. . . .  225 

XXL        Don'ts  for  Motor  Boatmen 243 

XXII.      Rules  of  Navigation 249 


CHAPTER  I. 
THE  MODERN   MOTOR  BOAT. 

The  modern  era  in  power  boating  dates  from  the  de- 
velopment for  marine  purposes  of  the  internal  combustion 
engine,  usually  employing  gasolene  as  fuel. 

For  small  self-propelled  craft  the  gasolene  engine  fur- 
nishes ideal  power.  Within  the  brief  span  of  the  last  few 
years  its  utility,  reliability  and  endurance  have  been  de- 
veloped to  a  point  nearing  perfection  as  far  as  pleasure 
craft  are  concerned,  while  its  use  for  passenger  transport 
and  other  business  purposes  is  steadily  increasing,  as, 
for  example,  in  the  towing  and  fishing  industries  of  the 
United  States  and  Canada.  In  fact,  it  has  already  meas- 
urably lessened  the  burdens  of  many  of  those  who  go 
down  to  the  sea  in  ships,  besides  adding  immeasurably  to 
the  delights  of  the  amateur  boatman  and  the  yachtsman. 

Among  the  advantages  accruing  from  the  use  of  the 
gasolene  engine  are  the  absence  of  smoke,  soot  and  heat, 
and  the  minimizing  of  the  work  required  in  the  operation 
of  a  power  boat.  The  boat-owner  can  be  his  own  engineer 
— and  therein  lies  the  secret  of  the  gasolene  motor's 
success. 

There  is  no  delay  in  starting  a  boat  with  a  gasolene 
motor — no  tiresome  waiting  to  get  up  steam ;  no  waste 
of  fuel  when  the  engine  is  standing  idle ;  no  need  to  don 
overalls  for  protection  against  grime  and  grease;  no 
stoking  or  coaling;  no  absolute  dependence  on  electric 
charging  stations.  The  main  essential  is  a  continuous 
gasolene  supply — and  that  can  be  replenished  almost  any- 
where at  comparatively  insignificant  cost. 


8  L'OTOR  BOATS: 

Just  as  the  gasolene  engine  has  revolutionized  land 
transport,  through  its  universal  use  in  the  automobile, 
so  it  is  having  a  great  effect  on  marine  transport,  es- 
pecially as  regards  the  thousands  who  take  their  pleasure 
afloat.  Even  the  vetreran  yachtsman,  wedded  to  his  ideas 
of  sporting  ethics,  has  been  converted  to  the  use  of  the 
motor  for  auxiliary  power — and  thereby  has  added  im- 
mensely to  his  comfort  and  to  his  enjoyment  of  his  white- 
winged  craft. 

While  the  landsman  has  had  a  hard  battle  to  fight, 
against  many  forms  of  prejudice  and  persecution,  while 
awaiting  public  recognition  of  the  "arrival"  of  the  motor 
car,  the  yachtsman  and  motor-boatman  have  had  no  such 
struggle  at  all.  The  sea  and  all  navigable  waters  spell 
freedom,  and  those  who  use  them  are  free  to  adopt  any 
form  of  propulsion  they  please.  It  has  been  well  said  that 
police  officers  do  not  lurk  afloat  in  unsuspected  places, 
ready  to  time  (with  watches  innocent  of  second  hands) 
any  motor-boat  passing  from  buoy  to  buoy,  so  that  they 
may  swear  to  impossible  records  of  speed  being  made, 
and  thus  enable  heavy  fines  to  be  imposed. 

The  practical  utility  of  the  gasolene  motor  having  been 
recognized  for  several  years,  it  has  gradually  dawned 
upon  the  public  that  its  reliability  and  endurance  have 
been  increasing  apace.  At  the  same  time  the  motor  has 
come  within  the  reach  of  those  of  moderate  means,  so 
that  today  not  only  can  the  sailing  yachtsman  with  a 
heavy  purse  equip  his  craft  with  an  efficient  auxiliary 
motor,  but  almost  any  man  can  have  a  self-propelled 
boat,  always  ready  at  a  minute's  notice  to  take  him  about 
on  the  water,  far  cheaper  to  buy  or  to  build  than  the 
smallest  steam  launch,  and  far  cheaper  to  operate  because 
he,  though  not  an  engineer  or  mechanic,  can  operate  it 
himself. 


CONSTRUCTIOX  AXD  OPERATIOX  9 

Amateur  Boat-Building. 

Amateur  builders  of  motor-boats  are  abroad  in  the  land 
in  ever  increasing  numbers.  The  old  idea  was  that  there 
are  many  technical  difficulties  in  the  way  of  those  who  do 
not  care,  or  have  not  the  time,  to  make  a  thorough  study 
of  the  subject.  Such  an  idea  is  a  mistake,  for  boat-build- 
ing is  well  worth  the  amateur's  attention,  and  is  really 
a  simple  craft.  Modern  methods  have  also  made  it  par- 
ticularly easy  for  the  amateur  to  construct  all  or  part  of 
his  boat. 

To  be  able  to  build  a  boat  well  and  to  his  own  ideas 
and  plans  requires  that  the  amateur  should  be  both  a  de- 


signer and  a  builder,  which  in  their  turn  require  that  he 
should  be  an  efficient  draftsman  and  carpenter.  No  one 
can  hope  to  succeed  in  building  a  boat  to  his  own  plan 
unless  he  is  fully  able  to  design  and  lay  down  the  lines 
and  body  plan  of  the  proposed  craft,  and  added  to  this  in 
many  kinds  of  boats,  such  as  a  sailing  boat  or  power 
launch,  it  is  necessary  that  he  should  be  able  to  calcu- 
late the  displacement  and  the  position  of  the  center  of 
buoyancy.  With  this  knowledge  at  his  command,  an 
unlimited  field  is  opened  to  the  amateur  boat-builder,  as 
he  will  be  able  to  build  after  his  own  ideas. 

Plans  and  patterns  can,  however,  now  be  purchased 
for  so  many  different  models  that  the  amateur  who  does 
not  care  to  attempt  designing  a  boat  has  the  choice  of 
many  tried  and  approved  designs  ready  to  his  hand  when 
he  starts  to  build  his  own  craft. 


10  MOTOR  BOATS: 

Choosing  an  Engine. 

When  buying  an  engine  the  novice  should  look  for  a 
simple  machine,  one  easy  to  keep  in  running  order,  and 
one  that  requires  the  least  possible  attention.  The  life 
of  an  engine  should  be  taken  into  consideration  very  care- 
fully, that  is,  how  long  will  the  different  parts  wear  be- 
fore they  have  to  be  replaced?  Are  the  bearings  and  the 
running  parts  of  the  engine  designed  to  stand  hard  work 
without  wearing  out  quickly?  Remember,  the  cheapest 
engine  in  the  end  to  buy  is  one  that  requires  the  least 
amount  of  repairs.  Every  part  of  a  good  modern  gasolene 
engine  can  be  readily  examined  and  adjusted  by  the 
operator  without  the  assistance  of  a  machine  shop. 

The  business  reputation  and  financial  responsibility 
of  the  manufacturers  are  factors  which  should  be 
considered  in  making  a  selection,  and  where  a  satis- 
factory choice  cannot  be  arrived  at  in  any  other 
manner,  these  points  should  be  carefully  considered 
in  making  the  purchase. 

There  are  four  essential  points  which  are  the  most 
vital  on  all  engines :  the  General  Construction,  the  Ig- 
niter, the  Carbureter,  and  the  Lubrication.  By  the  Gen- 
eral Construction  we  mean  the  materials  used  on  the 
engine,  the  workmanship  shown,  and  the  mechanical 
principles  underlying  the  work.  The  Igniter  transmits 
the  sparks  and  as  a  gasolene  engine  cannot  be  run  with- 
out a  spark,  this  point  is  rightly  reckoned  among  the  vital 
features.  The  Carbureter  mixes  the  gasolene  fuel  and  air 
to  form  the  gas  from  which  power  to  run  the  engine  is 
developed,  and  is  therefore  an  all-important  factor.  As 
regards  Lubrication,  every  engine  should  be  properly 
lubricated  to  run  successfully,  the  crank-pin  being  the 
hardest  to  oil.  The  mechanical  principles  of  all  two-cycle 
and  of  all  four-cycle  engines  are  similar,  but  the  other 
points  mentioned  are  not  and  it  is  these  points  that 
should  be  carefully  considered  in  choosing  an  engine. 


CONSTRUCTION  AND  OPERATION  11 

Before  buying  an  engine  of  any  particular  build,  the 
prospective  purchaser  should,  if  possible,  inspect  a  similar 
engine  in  operation,  doing  the  same  class  of  work  for 
which  he  requires  it.  He  should  examine  its  construction 
thoroughly,  study  its  principles,  and  learn  all  he  can  from 
the  owner  or  operator  as  to  its  behavior  under  varying 
circumstances — and  as  to  its  foibles.  Equipped  with  such 
information  he  will  welcome  the  arrival  of  his  new  en- 
gine with  a  better  understanding  of  what  he  may  expect 
from  it. 

A  16-foot  launch  with  a  \l/2  H.  P.  motor  will  have  a 
speed  of  about  7  miles  per  hour,  and  the  same  launch  with 
a  Zl/2  H.  P.  engine  will  have  a  speed  of  about  9  miles  per 
hour.  A  25-foot  runabout  with  a  5l/>  H.  P.  engine  will 
have  a  speed  of  8  miles  per  hour,  but  the  same  boat  may 
be  fitted  with  anything  up  to  a  25  H.  P.  engine,  with 
which  a  speed  of  about  21  miles  per  hour  can  be  reached. 
When  a  completed  hull  is  purchased  from  a  reputable 
builder  of  motor-boats  there  need  be  little  fear  of  in- 
stalling an  engine  which  the  hull  will  not  stand,  for  the 
boats  are  usually  guaranteed  to  stand  any  power*,  if  prop- 
erly installed,  that  the  hull  will  accommodate  for  space. 
Upon  being  informed  as  to  the  speed  desired  from  any 
stock  model  boat  the  builders  will  advise  the  purchaser 
as  to  the  engine  which,  in  their  opinion,  will  be  best 
adapted  for  it.  Some  builders  make  no  extra  charge  for 
installing  an  engine,  but  list  the  latter  separately  as  a  con- 
venient method  of  permitting  a  choice  of  power. 

Cabin  Cruisers. 

The  past  few  years  have  seen  a  wonderful  advancement 
in  the  construction  of  cruiser  craft.  In  the  past  decade  the 
gasolene  engine  and  the  motor-boat  have  revolutionized 
the  field  of  sport  and  recreation,  but  only  of  very  recent 
years  have  people  come  to  realize  the  real  utility  and 
practicability  of  the  cabin  cruiser,  and  that  such  boats  are 
capable  of  cruising  safely  in  any  waters  of  the  globe.  The 


12 


MOTOR  BOATS. 


four  boats  which  in  1909  entered  the  New  York  to  Ber- 
muda contest  ranged  only  from  42  to  85  feet  in  length  and 
raced  across  the  open  Atlantic  800  miles. 

To  anyone  living  upon  the  coast,  the  Great  Lakes,  the 
Mississippi  system,  or  any  of  the  rivers  tributary  thereto, 
the  cabin  cruiser  affords  the  greatest  opportunities  for 
healthful  and  delightful  recreation.  It  is  as  cool,  con- 
venient, and  comfortable  as  a  summer  cottage,  never 
grows  monotonous,  because  of  continual  change  of  scene, 
and  can  be  operated  at  very  small  expense.  Realizing  the 
advantages  of  this  type  of  boat,  and  that  its  popularity 
must  increase  with  each  succeeding  season,  the  leading 
boatbuilders  have,  during  the  past  few  years,  exerted 
every  possible  effort  to  perfect  the  design  of  their  models 
and  to  improve  the  interior  plans  in  order  to  secure  the 
greatest  serviceability  and  comfort,  and  the  most  pleasing 
general  appearance  at  the  least  possible  cost. 

"The  greatest  need  in  the  motor  and  boat  business," 
says  an  acknowledged  authority,  "is  more  information 
on  marine  engines."  We  shall,  therefore,  first  describe 
and  illustrate  the  principles,  construction  and  operation 
of  the  various  marine  gasolene  engines  in  present  day  use 
— and  then  proceed  to  the  subject  of  practical  boat- 
building. 


CHAPTER  II. 

MARINE  GASOLENE  ENGINES. 
1.     The  Four-Cycle  Type. 

Two  distinct  types  of  gasolene  engine  are  in  successful 
use  on  motor-boats,  these  being  known  respectively  as 
the  two-cycle  and  the  four-cycle  type. 

The  principle  of  operation  of  both  types  is  based  on 
the  now  well  known  facts  that  gasolene  vapor  or  a  fine 
spray  of  gasolene  when  mixed  with  air  forms  a  highly 
inflammable  mixture,  and  that  if  this  mixture  be  con- 
fined in  a  closed  chamber  and  ignited  by  a  flame  or  spark 
it  will  explode  and  expand.  This  is  just  what  is  done  in 
a  gasolene  engine,  the  expansion  being  used  as  the  motive 
power. 

In  modern  practice  the  engines  used  for  propelling 
motor-boats  and  launches  are,  in  the  great  majority  of 
cases,  of  the  internal  combustion  type,  using  gasolene 
(sometimes  kerosene)  as  fuel ;  the  exceptions  are  in  the 
case  of  steam  launches  and  electric  power  boats,  using 
respectively  steam  engines  and  electric  motors. 

In  all  engines,  of  whatever  type,  providing  a  source  of 
power,  something  must  be  consumed.  In  a  steam  engine 
coal  or  liquid  fuel  is  consumed  to  furnish  heat  and  the 
steam  generated  by  the  heat  given  off  is  used  to  produce 
power.  The  internal  combustion  engine  is  so  named  be- 
cause the  fuel  used  is  burned  or  consumed  inside  the 
engine  itself.  It  is  for  this  reason  that  it  forms  a  very 
simple  and  satisfactory  way  of  producing  power  for  dri- 
ving a  boat,  launch  or  yacht  and  is  in  increasing  use  for 
heavier  marine  duty. 


14  MOTOR  BOATS: 

Power  for  power,  the  internal  combustion  engine  is 
much  lighter  than  any  form  of  steam  engine  and  boiler, 
besides  having  other  very  important  advantages.  For  in- 
stance, the  steam  engine  is  at  a  disadvantage  in  com- 
parison with  the  gasolene  motor  in  that  an  additional 
process  is  passed  through  in  converting  the  fuel  into 
motion.  Thus  the  steps  are : 

Gasolene  motor — Fuel,  combustion,  motion. 

Steam  engine — Fuel,  combustion,  generation  of  steam, 
motionr 

And,  unfortunately  for  steam,  the  extra  step  always  in- 
volves the  expenditure  of  a  large  quantity  of  fuel.  Further^ 
the  steam  generator  or  boiler  occupies  a  lot  of  space  and 
much  time  is  required  in  getting  up  steam  for  the  start. 

An  internal  combustion  engine  can  use  various  kinds 
of  fuel,  but  all  of  them  are  hydrocarbons.  Heavy  oils 
are  used  in  some  marine  engines,  especially  for  what  is 
known  as  heavy  duty,  such  as  towing,  but  the  engine 
almost  universally  used  in  motor-boats  burns  the  very 
light  and  volatile  hydrocarbon  known  as  gasolene,  petrol 
or  petroleum  spirit.  It  is  from  this  that  the  gas  is  pro- 
duced which  is  burned  inside  the  engine. 

The  production  of  the  gas  from  the  hydrocarbon  is 
usually  obtained  by  means  of  a  carbureter.  In  a  few 
engines  the  carbureter  is  dispensed  with,  small  doses  of 
gasolene  being  injected  into  the  cylinder  at  frequent  inter- 
vals and  the  gasolene  mixture  formed  therein  as  required, 
but  this  is  an  exceptional  practice,  and  the  use  of  a  car- 
bureter is  the  rule. 

The  gas,  being  expansive  or  explosive  when  ignited, 
is  used  to  force  a  piston  of  a  cylinder  outward,  this  piston 
being  connected  by  means  of  a  connecting  rod  to  the 
crank  in  such  a  manner  that  when  it  is  forced  out  by  the 
expansion  of  the  gas  in  the  cylinder  it  turns  the  crank  and 
the  power  is  developed,  to  be  communicated  through  the 
shaft  to  the  propeller  wheel  at  the  stern. 


CONSTRUCTION  AND  OPERATION  15 

But  the  mechanism  which  is  required  to  produce  this 
apparently  simple  operation  has  other  functions  to  per- 
form, especially  in  the  case  of  the  earlier  form  of  internal 
combustion  engine  known  as  the  "four-cycle"  engine,  to 
which  we  will  first  refer. 

Before  the  gas  can  be  exploded  in  the  cylinder  it  is 
necessary  to  admit  it  or  draw  it  in,  which  means  that 
there  must  be  some  opening  in  the  cylinder  through 


Buffalo  4-cylinder,  10-40  H.  P.  Engine—Front  View. 
which  it  may  pass.  Before  it  can  be  exploded  so  that  it 
will  drive  the  piston  down  in  the  cylinder,  there  must  be 
some  means  of  closing  up  the  entrance  through  which 
it  has  passed  into  the  cylinder;  while,  again,  before  the 
operation  of  exploding  the  gas  can  be  repeated,  it  is  es- 
sential to  get  rid  of  the  exhaust  gases  generated  by  the 
explosion.  Also,  some  method  of  igniting  the  gas  so  as 
to  cause  it  to  expand  must  be  provided.  This  latter  re- 
quirement is  usually  attained  by  means  of  an  electric 
spark. 

Another  fact  to  be  noted  is  that  the  explosive  gas  drawn 
into  the  cylinder  will  give  out  greater  power  when  ig- 


16  MOTOR  BOATS: 

nited  if  it  is  first  compressed,  and,  therefore,  the  engine 
has  also  to  perform  the  function  of  compressing  the 
charge. 

Thus,  the  engine  has  four  different  duties  to  perform : 

First,  it  has  to  open  an  inlet  valve  and  to  draw  in  the 
charge. 

Second,  it  has  to  close  the  inlet  and  compress  the 
charge. 

Third,  it  has  to  fire  the  charge  so  as  to  force  the  piston 
out  to  do  work. 

Fourth,  it  has  to  expel  the  exhaust  gases. 

It  is  owing  to  these  four  operations  having  to  be  per- 
formed in  sequence  that  the  internal  combustion  engine 
of  this  type,  as  used  in  motor-boats,  is  known  as  a  "four- 
cycle" engine.  ,  The  term  is  somewhat  erroneous,  as  there 
is  but  one  true  cycle  of  operations,  embracing  four  steps 
or  parts. 

On  the  completion  of  the  four  steps  or  operations  all 
the  parts  of  the  engine  are  in  the  same  position  as  at  the 
beginning  and  the  four-step  cycle  of  operations  is  re- 
peated rapidly,  time  after  time,  as  long  as  the  engine  is 
kept  at  work.  The  cycle  includes  two  outward  and  two 
inward  strokes  of  the  piston,  or  four  in  all,  so  that  the 
flywheel  is  revolved  twice  during  each  complete  cycle. 
Working  of  the  Four-Cycle  Engine. 

In  the  illustrations,  Fig.  Nos.  1,  2,  3  and  4,  we  show  in 
diagrammatic  form  the  working  of  the  four-cycle  type  of 
internal  combustion  engine  used  in  many  motor-boats. 
In  arrangement  of  details  engines  vary  considerably,  but 
in  the  main  features  they  are  all  practically  alike.  A  i£ 
the  cylinder  and  B  is  the  movable  piston,  hollow  and  like 
an  inverted  tin  pail.  This  piston  B  is  capable  of  sliding 
freely  up  and  down  inside  the  cylinder  A,  but  it  is  pro- 
vided with  spring  rings,  which  make  it  fit  tightly  and 
prevent  any  gas  passing  by  it.  D  is  the  connecting  rod 
which  connects  the  piston  to  the  crank  E,  which  crank 


CONSTRUCTION  AND  OPERATION 


17 


forms  part  of  the  engine  shaft,  and  it  is  by  the  rotation 
of  this  that  the  boat  is  driven.  The  piston  B,  when  it  is 
forced  down  in  the  cylinder,  pushes  round  the  crank  E 
and  so  turns  the  shaft.  F  and  Fl  are  respectively  the 
inlet  and  exhaust  valves. 


V, 


SUCTION  STROKE. 


COMPRESSION  STROKR 


The  gas  from  the  carbureter  enters  at  G  and  after  hav- 
ing been  ignited  is  expelled  through  the  port  Gl.  The 
valves  F  and  Fl  are  operated  by  the  engine  itself  by 
means  of  cams  H  and  HI.  These  cams  are  carried  on 
shafts  which  are  driven  by  the  engine  crankshaft,  but  at 
half  its  speed.  The  dotted  lines  indicate  the  gear  wheels 
on  the  two  shafts  and  on  the  engine,  by  means  of  which 
the  shafts  are  rotated.  It  will  be  seen  that  the  cam  on 
either  of  these  shafts  will  lift  its  valve  once  in  every  two 
revolutions  of  the  crankshaft. 

In  Fig.  No.  1  we  see  that  the  cam  has  lifted  the  inlet 
valve  F.  At  the  same  time  the  crank  is  in  such  a  position 
that,  the  piston  is  just  descending  in  the  cylinder.  As 
the  piston  descends  it  acts  as  a  suction  pump  and  draws 


18 


MOTOR  BOATS: 


in  the  gas  from  the  carbureter  through  the  valve  port  G. 
As  soon  as  the  piston  has  reached  the  bottom  of  its 
stroke  the  cam  H  allows  the  valve  F  to  fall  on  its  seat. 
The  flywheel  on  the  crankshaft  of  the  engine,  however, 
through  its  stored  momentum,  continues  to  rotate  the 
crank,  and,  therefore,  the  piston  B  is  pushed  back  again 
into  the  cylinder  (Fig.  No.  2),  but  as  now  there  is  no 
exit  from  the  cylinder,  the  gas  inside  it  is  compressed 
into  the  combustion  space.  This  compression  proceeds 


N°3 


POWER  STROKE. 


EXHAUST  STROKE, 


until  the  piston  has  reached  the  top  of  its  stroke,  and  at 
this  point  a  spark  is  caused  to  pass  across  the  points  of 
the  spark  plug  J.  As  soon  as  this  occurs,  the  gas  charge 
is  ignited  and  expands  very  rapidly,  this  expansion  for- 
cing the  piston  B  down  in  the  cylinder  and,  through  the 
medium  of  the  connecting  rod,  turning  the  crank  E.  This 
is  the  power  stroke  (Fig.  No.  3). 

Immediately  before  the  piston  reaches  the  bottom  of 
its  stroke,  the  cam  HI  lifts  the  exhaust  valve  Fl,  the  inlet 
valve  F  of  course  remaining  closed.  The  momentum  of 
the  flywheel  carries  the  crank  round  and  forces  the  piston 


CONSTRUCTION  AND  OPERATION  19 

back  up  the  cylinder,  it  in  turn  forcing  the  exhaust  gases 
out  through  the  exhaust  port  Gl.  This  is  the  exhaust 
stroke  (Fig.  No.  4). 

The  engine  is  now  in  a  position  to  perform  the  same 
cycle  of  operations  as  before,  the  next  stroke  drawing  the 
piston  down  and  bringing  in  a  fresh  charge  through  the 
inlet  G,  which  in  turn  is  compressed,  ignited  and  ex- 
pelled as  before.  It  will  thus  be  seen  that  the  engine 
during  two  revolutions  of  the  crankshaft  has  performed 
the  four  operations  which  are  necessary  to  its  proper 
working.  The  operations  in  sequence  are  as  follows : 

1.  Down  stroke  of  the  piston — Gas  charge  is  drawn  in. 

2.  Up  stroke  of  the  piston — Gas  charge  is  compressed. 

3.  Down  stroke  of  the  piston — Gas  charge,  being  ig- 
nited, is  rapidly  expanding. 

4.  Up  stroke  of  the  piston — The  exhaust  gases  are  be- 
ing expelled. 

These  four  strokes  of  the  piston,  respectively,  are 
known  as  the  Suction,  Compression,  Power  and  Exhaust 
strokes,  as  indicated  under  the  diagrams. 

As  the  initial  operation  is  to  draw  in  a  charge  of  gas, 
it  will  be  seen  that  before  the  engine  can  be  started  it 
is  necessary  to  rotate  the  crankshaft,  by  turning  the 
flywheel  or  some  starting  device,  a  starting  crank  or 
starting  ratchet  and  lever,  so  that  a  charge  is  drawn  in 
and  compressed.  This  is  then  fired  and  the  engine  will 
continue  to  operate  automatically. 


CHAPTER  III. 

MARINE  GASOLENE  ENGINES. 

2.    The  Two-Cycle  Type. 

In  modern  motor-boat  practice,  especially  for  the 
smaller  boats,  the  two-cycle  type  of  gasolene  engine  is 
now  in  large  and  growing  demand.  Various  advantages 
are  claimed  for  it,  among  these  being  (a)  the  small  num- 
ber of  moving  parts — namely,  the  piston,  connecting  rod 
and  crankshaft  with  flywheel;  (b)  adaptability  for  re- 
versing, the  engine  running  equally  well  in  either  direc- 
tion ;  (c)  absence  of  complicated  valves,  cams,  etc. ;  (d) 
simplicity  and  reliability. 

The  word  "cycle"  can  be  defined  as  "a  succession  of 
events  necessary  to  complete  an  operation."  For  in- 
stance, every  internal  combustion  engine  when  running 
does  the  four  following  things  every  time  it  produces  a 
power  impulse : 

First,  draws  in  a  charge  of  explosive  mixture. 

Second,  compresses  this  charge. 

Third,  fires  or  expands  the  charge. 

Fourth,  exhausts  the  burned  or  expanded  charge. 

The  four-stroke  engine  (commonly  called  four-cycle 
engine)  requires  four  strokes  of  the  piston,  two  up  and 
two  down  (or  two  revolutions)  to  complete  the  above 
cycle  and,  therefore,  operates  in  a  four:stroke  cycle. 

The  two-stroke  (commonly  called  two-cycle  engine) 
performs  all  of  the  above  functions  with  two  strokes  of 
the  piston,  one  up  and  one  down  (or  one  revolution)  and, 
therefore,  operates  in  a  two-stroke  cycle. 


•   CONSTRUCTION  AND  OPERATION 


21 


In  the  two-stroke  or  two-cycle  engine  of  the  internal 
combustion  type  there  is  an  explosion  of  the  fuel  mix- 
ture at  every  revolution  of  the  crankshaft.  In  this  type 
of  engine  the  cylinder  is  not  utilized  for  the  purpose  of 
compressing  the  charge,  although  the  piston  is.  £the 
airtight  crankcase  acts  as  a  supplementary  air-chamber 
into  which  the  gas  to  be  exploded  caji  be  drawn  and  then 
forced  into  the  cylinder  under  pressur,e\  The  incoming 
gas  charge  forces  the  exhaust  gases  out/ 


FIG.  »  .—A  TWO-CYCLE  ENGINR 

A  diagrammatic  view  of  a  simple  arrangement  of  the 
two-cycle  engine  (which  is  made  in  a  great  many  differ- 
ent designs)  is  shown  -herewith.  A  is  the,  cylinder  and 
B  the  piston,  D  the  connecting  rod  and  E  the  crank.  The 
crank-case  O  is  made  as  airtight  as  possible  and  an  auto- 
matic inlet  valve  F  is  arranged  so  as  to  admit  the  gas  to 
the  crank  chamber.  There  is  a  pipe  leading  from  the 
crank  chamber  to  the  inside  of  the  cylinder  A,  this  pipe 
being  shown  at  G.  When  the  piston  is  at  the  bottom  of 


22  MOTOR  BOATS: 

its  stroke  it  uncovers  the  top  of  the  pipe  G,  so  that  the 
cylinder  A  comes  into  communication  with  the  crank- 
case  O. 

P  is  the  exhaust  port,  which  is  uncovered  by  the  piston 
when  it  reaches  the  bottom  of  its  stroke.  Q  is  a  baffle 
plate,  which,  when  the  piston  has  opened  the  top  of  the 
pipe  G,  comes  opposite  to  that  opening  and  directs  the 
incoming  gas  charge  in  an  upward  direction.  The  cycle 
of  operations  is  as  follows : 

The  first  upstroke  of  the  piston  draws  the  charge  of 
gas  into  the  crank-case  through  the  valve  F.  The  piston 
then  descends,  compressing  the  gas  charge  in  the  crank- 
case.  When  it  reaches  that  point  at  which  the  top  of  the 
pipe  G  is  uncovered,  the  compressed  gases  in  the  crank- 
case  rush  through  the  pipe  G  into  the  cylinder  A.  The 
piston  then  ascends  and  when  it  reaches  the  top  of  its 
stroke  the  charge  is  fired  and  the  piston  descends  until  it 
reaches  that  point  at  which  the  exhaust  port  P  is  un- 
'covered.  This  is  the  power  stroke,  following  the  impulse 
of  the  explosion  and  expansion  of  the  gaseous  charge. 
During  this  power  stroke  another  charge  of  gas,  which 
came  into  the  crank  chamber  owing  to  the  upward  suc- 
tion of  the  piston,  is  being  compressed,  and  just  after 
the  exhaust  P  is  opened  this  compressed  charge  rushes 
up  through  pipe  G  into  cylinder  A ;  the  returning  piston 
further  compresses  it  there,  and  when  it  is  at  the  top  of 
its  stroke  the  charge  is  fired.  The  incoming  charge,  during 
the  time  that  the  piston  B  has  uncovered  both  the  ex- 
haust port  P  and  the  top  of  G,  violently  pushes  the  ex- 
haust gases  out  through  P.  By  this  arrangement  an  im- 
pulse is  given  to  the  piston  on  each  revolution,  so  that 
there  is  no  need  for  any  mechanically  operated  valve, 
the  only  valve  being  the  automatic  one  at  F.  Such  en- 
gines, though  not  largely  used  for  motor  vehicle  pur- 
poses, are  very  popular  for  motor-boats  and,  in  fact,  for 


CONSTRUCTION  AND  OPERATION  23 

this  purpose  have  proved  themselves  to  be  among  the 
most  efficient  of  internal  combustion  engines. 

The  "Three-Port"  Type. 

In  some  two-cycle  engines  the  necessity  for  a  check 
valve  leading  to  the  crank-case  is  avoided  by  what  is 
known  as  the  "three-port"  design.  In  this  type  of  engine 
the  piston  creates  a  partial  vacuum  in  the  crank-case 
by  its  upward  movement,  and  no  fresh  charge  is  taken 
in  until  near  the  end  of  the  up-stroke,  when  the  lower 
edge  of  the  piston  uncovers  a  port  through  which  the 
fresh  charge  enters  with  a  rush. 


Knox  Single- Cylinder,  2-cycle,  3-port  Engine. 

The  successful  performance  of  a  two-cycle  engine  de- 
pends on  the  correct  design  of  the  exhaust  and  transfer 
ports  and  the  baffle  plate  or  deflector,  all  of  which  are 
matters  for  experiment.  It  also  depends  on  the  piston  be- 
ing a  reasonably  good  fit  in  the  cylinder,  since  a  loose 
piston  allows  the  compressed  charge  in  the  crank-case 
to  leak  past  it  out  of  the  exhaust  port.  It  is  further 
necessary  to  have  the  crank-case  substantially  airtight 
and  to  adopt  suitable  means  to  prevent  blowing  by  the 
crankshaft  bearings.  For  this  reason,  grease  is  largely 
used  for  bearing  lubrication  in  these  engines. 

Two-cycle  engines  are  frequenty  oiled  on  the  splash 
system,  but  this  is  considered  by  other  engine-builders 


24 


MOTOR   BOATS: 


to  be  wasteful  of  oil,  since  an  unnecessary  amount  of  oil 
spray  is  carried  into  the  cylinder  through  the  transfer 
port.  Some  engines  have  mechanical  oilers  and  use 
special  means  of  conveying  oil  to  the  crank  pin  and 
piston. 

A  two-cycle  engine  will  run  in  one  direction  as  well  as 
the  other.  A  four-cycle  engine  runs  in  only  one  direction, 
unless  a  special  arrangement  is  used  to  open  the  valves  at 
the  proper  time  for  reversing. 


The  Two-Cycle  Detroit  Engine. 


A — Cylinder. 

B— Piston. 

C — Crank-case. 

D — Connecting  rod. 

E — Exhaust  port. 

F — Expansion  chamber. 

G — Exhaust    pipe. 


H— Inlet   port. 

I — Transfer  passage  from  cylin- 
der to  crank-case. 
K — Spark  plug. 
L — Carbureter. 
M — Deflector  or  baffle  plate. 


CONSTRUCTION  AND   OPERATION  25 

A  Typical  Two-Cycle  Engine. 

The  actual  working  of  a  typical  two-cycle  engine  is 
explained  by  means  of  the  illustration  as  follows : 

We  will  start  with  cylinder  A  full  of  fresh  mixture. 
Piston  B  travels  upward  drawing  a  mixture  of  air  and 
-gasolene  from  carbureter  L  through  inlet  into  crank-case 
C.  At  the  same  time  it  compresses  the  fresh  mixture  in 
cylinder  A,  at  the  top  center  an  electric  spark  is  thrown 
across  the  points  of  spark  plug  K  which  lights  the  charge 
and  makes  it  expand  and  drive  the  piston  downward, 
while  the  gas  in  the  crank-case  C,  being  held  in  same  by 
non-return  valve  in  carbureter,  is  slightly  compressed. 
The  piston  first  uncovers  the  exhaust  port  E  and  the 
highly  expanded  gases  pass  out  of  same  into  expansion 
chamber  F,  where  they  are  instantly  condensed  by  a  fine 
spray  of  water.  The  inlet  port  H  opens  and  admits  the 
gas  compressed'  in  the  crank-case — which  rushes  up 
through  passage  I  to  fill  the  cylinder.  This  gas  strikes 
the  deflector  plate  M  and  shoots  straight  toward  the  top 
of  the  cylinder.  As  the  port  opens  to  full  width  the 
stream  of  gas  traces  a  fan-shaped  path  and  blows  before 
it  all  the  remainder  of  the  burned  gas  from  the  previous 
explosion. 

The  Offset  Cylinder. 

The  efficiency  of  the  modern  gasolene  engine  is  in- 
creased by  the  adoption  of  what  is  known  as  the  "offset" 
cylinder,  which  slightly  increases  the  length  of  the  stroke 
and  secures  a  more  direct  effect  upon  the  crank  at  the 
time  the  explosion  occurs. 

A  good  idea  of  the  construction  of*  the  offset  cylinder 
can  be  drawn  from  the  illustrations,  figures  1  and  3.  It 
will  be  observed  that  with  the  piston  at  the  top  of  stroke, 
its  center,  as  compared  with  the  center  of  crankshaft,  has 
a  slight  deviation.  Fig.  2  shows  the  usual  method  of  con- 


26 


MOTOR  BOATS: 


struction  with  the  center  of  both  crankshaft  and  cylinder 
in  perfect  alignment. 

It  is  the  common  practice  of  motor-boat  men  to  operate 
their  engines,  while  at  cruising  speed,  on  either  a  late 
spark  or  with  the  firing  point  at  the  top  of  the  piston 
stroke.  In  the  latter  case  by  reference  to  Fig.  3  it  will  be 
observed  that  the  impulse  of  the*  explosion  is  not  directed 


upon  the  dead  ce,nter  as  in  Fig.  2,  but  the  transmission  of 
the  energy  is  exerted  upon  the  crankshaft  in  a  turning 
position  as  in  Fig.  3.  The  connecting  rod  in  descending 
on  the  impulse  stroke  has  practically  a  vertical  position, 
thus  more  directly  transmitting  :he  energy  from  the 
piston  to  the  crankshaft. 

The  offset  cylinder  procures  from  the  motor  it3  maxi- 
mum  power   and   efficiency,    reduces   and   equalizes   the 


CONSTRUCTION  AND  OPERATION 


> 
27 


side  thrust  upon  the  cylinder  wall  on  the  impulse  stroke 
and  furthermore  eliminates  the  knock  which  always  tends 
towards  loosening  of  parts,  and  premature  decay  of  the 
motor. 

The  line  drawing,  Fig.  2,  represents  the  ordinary  con- 
struction with  straight  center  line.  The  position  of  the 
piston  as  shown  is  at  explosion  center.  The  explosion 
exerts  no  turning  effort  to  the  crankshaft,  for  the  thrust 
is  exerted  on  the  dead  center  and  falls  on  the  bearings. 


Fig.  2;  Fig.  3 

In  Fig.  3,  the  offset  construction  is  represented  with 
the  piston  in  same  position  as  Fig.  2,  at  firing  center.  It 
will  be  observed  that  the  crank,  however,  is  not  at  dead 
center,  and  that  the  impulse  or  thrust  will  be  imparted 
to  it  in  a  turning  position.  No  energy  is  wasted,  and  no 
undue  shock  is  given  the  bearings. 

Kerosene  Fuel  Devices. 

There  is  a  growing  demand  for  engines  that  will  use 
kerosene  as  fuel,  and  manufacturers  have  recently  been 
giving'some  attention  to  this  matter,  with  the  result  that 
there  are  now  in  the  market  a  number  of  engines  that, 
it  is  claimed,  will  burn  kerosene,  distillate,  naphtha, 


28  MOTOR  BOATS: 

benzine,  alcohol,  etc.,  as  well  as  gasolene.  The  usual 
plan  is  to  start  the  engine  on  gasolene,  the"n  shut  off  the 
gasolene  supply  and  turn  on  kerosene,  etc.  Special  in- 
structions for  the  use  of  other  fuels  are  issued  by  the 
engine-builders  and  these  must  be  carefully  followed  to 
secure  good  results. 

The  Detroit  twp-cycle  engine,  built  by  the  Detroit 
Engine  Works,  is  fitted  with  a  device  known  as  the 
Detroit  fuel  injector  when  kerosene  or  other  fuels  than 
gasolene  are  to  be  used,  and  it  is  understood  good  results 
are  thus  obtained.  This  device  is  not  applicable  to  four- 
cycle engines. 

The  Buffalo  Gas  Motor  Company  has  evolved  a  kero- 
sene device  for  its  four-cycle  Buffalo  engines,  starting 
on  gasolene,  but  an  engine  so  arranged  will  not  show  full 
power  on  gasolene  only,  as  kerosene  being  a  heavier  fuel 
compression  in  a  kerosene  engine  must  necessarily  be 
lower  than  in  a  regular  gasolene  engine. 

Ferro  motors  and  others  can  also  be  run  on  kerosene, 
and  the  use  of  this  fuel  may  be  developed  to  give  more 
generally  satisfactory  results.  The  increasing  price  of 
gasolene  is  an  important  factor  in  the  operation  of  in- 
ternal combustion  engines  and  a  cheaper  fuel  will  be 
welcomed. 

One  present  difficulty  with  kerosene  is  its  tendency  to 
deposit  carbon  in  the  cylinder  and  on  the  piston  and 
rings — for  which  the  only  remedy  is  to  take  out  the  piston 
and  remove  the  deposits. 

Naphtha  Engines. 

The  naphtha  launch  was  the  immediate  precursor  of 
the  modern  gasolene  craft,  and  was  popular  for  over 
twenty  years.  Its  extreme  simplicity  in  operation,  its 
reliability  and  safety,  commended  it  everywhere,  and 
only  the  largely  increased  cost  of  the  fuel  •  militated 
against  its  use  where  economy  was  a  primary  considera- 
tion. The  consumption  of  fuel,  however,  in  the  smaller 


CONSTRUCTION  AND  OPERATION 


29 


sizes,  1  to  10  horsepower,  is  not  so  material  as  to  be  of 
much  weight.  For  use  in  launches  of  16  to  30  feet,  and 
especially  for  tenders  on  large  yachts,  the  naphtha  en- 
gine is  still  much  in  evidence.  The  illustrations  show 
the  form  of  naphtha  engines  of  recent  construction. 


Naphtha  Engines. 


CHAPTER  IV. 

CARBURATION  AND  CARBURETERS. 

Gasolene  vapor  being  explosive  only  when  mixed  with 
air  in  approximately  such  proportions  that  each  molecule 
of  vapor  finds  a  certain  quota  of  oxygen,  a  mechanical 
device  to  secure  the  proper  mixture  is  an  essential  part 
of  a  gasolene  engine.  Mixtures,  which  are  either  too 
"rich"  or  too  "lean" — that  is,  those  in  which  there  is  too 
great  or  too  small  a  proportion  of  gasolene  vapor — are 
not  explosive,  and  are  ignited  with  difficulty,  thereby  in- 
terfering with  the  proper  running  of  the  engine. 

The  carbureter  is  the  device  usually  employed  to  feed 
the  gasolene  to  an  air  stream  in  suitable  proportions  to 
form  an  explosive  mixture.  In  the  commonest  form  of 
this  device,  a  stream  of  air  is  drawn  at  high  velocity  past 
a  nozzle,  from  which  the  gasolene  is  sucked  and  broken 
into  spray,  the  gasolene  entering  the  carbureter  by  grav- 
ity from  the  supply  tank,  a  means  of  control  being  duly 
provided. 

Numerous  forms  of  carbureters  are  employed  with  gas- 
olene engines,  but  the  type  almost  universal  on  motor- 
boats  is  the  spray  carbureter.  In  this,  the  gasolene  is 
drawn  through  a  nozzle  or  jet  by  the  engine,  and  as  it 
leaves  the  jet  in  the  form  of  spray,  it  mixes  with  air 
which  is  sucked  into  the  engine  at  the  same  time. 

The  Float-Feed  Principle. 

Now,  as  the  air  must  be  charged  with  a  certain  pro- 
portion of  gasolene  vapor  in  order  to  obtain  the  best 
results,  it  will  be  apparent  that  the  form  and  dimensions 


CONSTRUCTION  AND  OPERATION 


31 


of  the  carbureter  must  be  carefully  designed,  and  that 
the  flow  of  gasolene  must  be  properly  regulated.  To  ac- 
complish the  second  object,  a  float  valve  is  employed. 
Instead  of  being  led  directly  to  the  nozzle  the  gasolene 
is  fed  through  a  pipe  into  a  chamber  in  which  is  a  float; 
nearly  filling  the  same. 

In  some  carbureters  the  floats  are  principally  made  of 
cork,  but  they  are  generally  constructed  of  thin  metal. 


The  Ferro  Carbureter. 

Pivoted  to  the  top  and  bottom  of  the  chamber  of  a  typi- 
cal carbureter  are  two  weighted  levers.  The  outer  ends 
of  these  levers  bear  against  the  float ;  the  inner  ends  en- 
gage in  a  grooved  collar  fixed  to  a  wire  or  needle.  This 
needle  has  a  conical  point  adapted  to  fit  into  a  cor- 
responding conical  seating  at  the  point  where  the  gaso- 
lene enters  the  chamber.  As  the  gasolene  gets  deeper  in 
the  chamber  it  raises  the  float,  the  outer  ends  of  the 
lever  rise,  the  inner  ends  are  forced  down,  and  the  pointed 
end  of  the  needle  is  thrust  farther  and  farther  into  the 
seating,  so  that  when  the  gasolene  has  reached  the  de- 
sired height  in  the  chamber  the  supply  is  cut  off. 

There  is  a  small  passage  communicating  between  the 
float  chamber  and  the  nozzle,  consequently  the  gasolene 
will  stand  at  the  same  height  in  the  nozzle  as  in  the 
chamber.  Usually  the  float  valve  device  is  arranged  to 


32  MOTOR   BOATS: 

keep  the  gasolene  at  about  one-sixteenth  inch  below  the 
level  of  the  top  of  the  jet. 

More  gasolene  vapor  being  sucked  into  the  engine 
when  it  is  running  at  high  speed,  a  proper  air  supply  is 
important  to  maintain  a  mixture  of  the  same  proportions 
at  high  and  low  speeds.  To  meet  this  requirement  nu- 
merous forms  of  automatic  carbureters  have  been  de- 
vised, most  of  which  admit  additional  air  at  high  speeds 
by  a  light  valve  opening  against  a  spring.  This  is  usually 
called  an  auxiliary  air  valve  and  the  air  thus  automatically 
admitted  at  high  speeds,  reduces  the  richness  of  the  mix- 
ture to  the  proper  point. 

Regulation  of  Spray  Carbureters. 

The  flow  of  gasolene  through  the  spray  orifice  is  con- 
trolled either  by  an  adjustable  needle  valve  or  by  regu- 
lating the  opening  of  the  air  intake.  Reducing  the  size 
of  this  intake  increases  the  suction  and  therefore  the 
richness  of  the  mixture,  unless  the  auxiliary  intake  is 
separate,  in  which  case  reducing  the  primary  intake  weak- 
ens the  mixture  after  the  auxiliary  valve  is  open.  Chan- 
ging either  the  needle  valve  or  the  primary  air  intake  will 
increase  or  diminish  the  gasolene  supply  at  all  speeds, 
It  is  customary  in  adjusting  a  carbureter  to  begin  by 
setting  the  needle  valve  or  the  primary  air  intake  to  give 
a  good  mixture  when  the  engine  is  running  on  a  low 
throttle  with  little  or  no  opening  of  the  auxiliary  air 
valve.  This  insures  easy  starting  and  good  control  at  low 
speeds.  For  medium  and  high  speeds  the  auxiliary  air 
valve  is  adjusted  by  regulating  its  spring  tension  and  its 
maximum  opening  at  high  speed. 

The   Mixing  Valve  or  Vaporizer. 

If  a  marine  engine  is  to  be  run  at  approximately  one 
speed  all  the  time,  a  simple  mixing  valve  is  often  found 
to  give  good  results.  With  this  device,  however,  the 
mixture  must  be  regulated  by  hand.  This  was  the 
original  method  of  mixing  gasolene  vapor  and  air  in 


CONSTRUCTION  AXD   OPpRATIOX  33 

due  proportions  for  combustion  and  the  device  is  vari- 
ously called  a  mixing  valve,  generator  or  vaporizer.  It 
consists  chiefly  of  an  air  chamber  or  passage  -in  which  a 
needle  valve  is  situated.  This  valve  is  practically  the 
same  as  the  needle  valve  on  the  common  gasolene  stove 
in  that-  it  sprays  the  gasolene  into  the  burner.  The 
burner  in  the  stove  would  represent  the  mixing  chamber. 
In  connection  with  this  passage  or  mixing  chamber  with 
its  gasolene  valve  is  a  check  or  disk  valve  which  operates 
in  holding  the  vaporous  gases  in  the  motor  as  they  pass 
from  the  mixer.  At  every  up  stroke  of  the  engine  piston, 
with  the  two-cycle  motor,  the  partial  vacuum  or  suction 
in  the  crank-case  causes  an  influx  of  air  through  the  mix- 
ing valve.  The  force  of  the  incoming  air  lifts  the  check 
valve.  This  valve  when  it  lifts,  uncovers  a  small  gaso- 
lene port,  allowing  it  to  spray  the  liquid  into  the  air 
chamber,  and  become  mixed  with  the  inrushing  air. 
When  the  engine  piston  starts  downward,  compressing 
the  charge  in  the  base,  the  check  valve  closes,  holding  the 
charge  and  also  closing  the  gasolene  port  until  the  next 
similar  operation.- 

This  type  of  generator  works  very  successfully  but 
lacks  the  feature  of  a  steady  constant  feed  of  gasolene 
where  the  gravity  flow  varies,  as  it  does  with  a  full  or 
nearly  empty  gasolene  tank.  Again  the  varying  speeds 
of  the  motor  will  affect  the  feed  of  gasolene  into  the  mix- 
ing chamber.  In  both  these  cases  it  requires- an  adjust- 
ment of  the  needle  valve,  by  the  operator.  This  feature 
•  of  constant  care  with  the  generator  valve  is  often  a  worry 
to  the  operator  under  the  conditions  mentioned. 

The  improved  float-feed  type  of  carbureter  is  designed 
to  obviate  the  difficulty  of  maintaining  a  constant  flow 
of  gasolene  under  all  circumstances. 

The  "Puddle"  Type. 
In  a  ne\v  form  of  carbureter  known  as  the  puddle  type. 


:M  MOTOR  BOATS: 

a  lloat  maintains  the  gasolene  nozzle  at  such  a  level  that 
il  forms  a  small  puddle  in  the  bottom  of  a  I  '-shaped  mix-' 
\i\g  tube.  J'he  intlow  of  gasolene  to  this  puddle  is  COn- 
trolled  by  a  needle  valve-  and  this  adjustment,  in 
connection  with  the  depth  of  the  puddle  itself,  determines 
the  ipiality  of  the'  mixture.  This  carbureter  does  not  act 
by  spraying  except  at  hi^h  speeds.  At  all  lower  speeds 
the  gasolene  is  simply  swept  alon^  the  walls  of  the  intake 
pipe  and  evaporated,  The  essential  difference  between 
the  puddle  and  the"  spraying  types  is  that  in  the  formcr 
the  gasolene  feeds  itself  to  the1  air  at  low  speeds,  instead 
of  re'(|uirini;-  a  certain  minimum  decree  of  suction  for  that 
purpose-.  It  will  therefore  make  a  mixture'  at  lower 
speeds  than  the  ordinary  spraying  carbureter.  It  has, 
however,  certain  peculiarities  in  operation,  and  very  ac- 
curate' adjustment  of  the  lloat  is  necessary  to  prevent 
Over  richness  of  the'  mixture'. 


Schebler  Carbureter,  Model  D— Front  View. 

The  Schebler  float-feed  carbureter  in  use  on  many 
motor-boats  is  known  as  Model  \\  and  is  illustrated  here- 
with. It  is  manufactured  by  \\  heeler  \  Schebler,  of 


CONSTRUCTION  AXD  OPERATION 


35 


Indianapolis,  and  is  made  in  four  pipe  sizes,  from  one  to 
two  inches.  It  has  been  improved  recently  by  the  addi- 
tion of  a  butterfly  shutter  placed  in  the  air  intake.  This 
should  be  attached  to  a  wire,  running  to  some  convenient 
place  near  the  starting  crank.  When  cranking,  pull  the 
shutter  closed.  This  draws  a  rich  mixture  into  the  cyl- 
inders, causing  the  motor  to  start  on  the  first  or  second 
turn  of  the  crank. 


MODEL   D 


J-M. 


Schebler  Carbureter,  Model  D — Section. 

.other  improvement  has  been  made  on  the  air  valve 
adjusting  screw.  A  -trong  friction  spring  is  placed 
around  the  adjusting  screw  between  the  lock  nut  and  air 
valve  casting,  preventing  the  lock  nut  from  jarring  loose 
and  thus  allowing  the  air  adjustment  to  change. 


I 


b 
£ 


10 

bio 


CHAPTER  V. 

IGNITION. 

In  order  to  explode  the  charge  of  vaporous  gases  that 
are  drawn  into  the  cylinder  of  an  internal  combustion 
engine,  some  means  must  be  provided  for  supplying  heat 
in  the  proper  amount  and  at  the  proper  time.  This  heat 
may  be  furnished  by  various  methods,  namely,  the  hot 
tube,  the  incandescent  filament,  a  heated  surface 
or  an  electric  spark.  The  first  three  methods,  illus- 
trated in  Figs.  1,  2  and  3,  belong  to  the  period  of  de- 
velopment of  the  gasolene  engine  and  are  practically 
obsolete.  (See  full  page  illustration.) 

With  the  electric  spark,  Fig.  4,  the  method  consists 
of  sending  an  electric  current  to  a  spark  coil,  where  it 
is  transformed  and  sent  on  to  the  spark  plug  in  the  top  of 
the  cylinder,  terminating  in  two  points  of  the  plug  which 
are  separated  about  one  thirty-second  of  an  inch  from 
each  other.  At  the  proper  time  the  current  is  sent 
through  these  wires,  causing  a  spark  in  the  cylinder  at 
the  spark  plug.  This  method  is  in  universal  use  today. 
Its  advantages  over  the  old  time  system  of  the  hot  tube, 
the  heated  surface  and  the  filament,  lie  in  the  fact  that  it 
is  simple,  more  reliable  and  easily  controlled. 

There  are  two  distinct  kinds  of  electric  current  in  use, 
namely,  the  high  tension  or  jump  spark  and  the  low 
tension  or  make  and  break  spark.  Briefly,  the  high  ten- 
sion system  consists  of  leading  an  electric  current  from 
dry  or  wet  batteries,  magneto  or  dynamo  to  a  trans- 
former or  spark  coil,  thence  to  the  spark  plug,  Fig.  5, 
which  is  usually  located  on  the  top  of  the  cylinder.  In 
order  to  control  this  spark,  that  is,  to  make  the  spark 


38  MOTOR  BOATS: 

occur  at  just  the  proper  moment,  the  current  is  thrown 
on  and  off  by  the  use  of  a  sparking  device  or  timer,  lo- 
cated outside  the  cylinder.  When  the  current  is  thrown 
on,  a  spark  jumps  across  the  gap  at  the  spark  plug  S-T 
inside  the  cylinder,  thus  igniting  the  charge. 

A  low  tension  system  consists  chiefly  of  leading  an 
electric  current  to  a  coil,  whose  -functions  are  not  the 
same  as  the  coil  used  in  the  jump  spark  system.  From 
this  coil  the  current  is  led  to  two  movable  contact  pieces 
inside  the  cylinder.  (See  Fig.  6.)  These  contact  pieces 
are  operated  from  without  in  such  a  manner  that  they 
come  together  and  separate  at  just  the  proper  moment 
to  make  a  spark  and  ignite  the  charge. 

The  electric  current  used  in  producing  the  spark  is 
usually  drawn  from  one  of  three  sources:  1,  a  dry  cell; 
2,  the  storage  battery;  3,  the  magneto  or  dynamo. 

Dry  Cells. 

The  dry  cell  (group  Fig.  5)  consists  usually  of  a  carbon 
and  zinc  element  immersed  in  moistened  salts.  By 
chemical  action  this  combination  has  the  power  of  de- 
livering an  electric  current.  Since  the  gasolene  engine 
has  come  into  prominence  and  the  demand  for  an  effi- 
cient, reliable  and  inexpensive  source  of  current  supply 
has  been  developed,  the  dry  cell  has  been  brought  to 
commercial  perfection.  It  is  clean,  not  very  heavy  and 
occupies  a  small  amount  of  space.  A  set  of  dry  cells  is 
regularly  supplied  with  the  best  marine  engine  outfits. 
If  properly  installed,  the  dry  cell  will  last  a  long  time 
and  any  one  cell  may  be  removed  from  the  set  if  de- 
fective and  replaced  by  a  new  one. 

Wet  Batteries. 

Wet  batteries  have  become  very  popular  for  some 
classes  of  marine  ignition  work.  There  are  a  great 
many  different  companies  supplying  batteries  of  the  wet 
type  that  are  very  efficient.  In  purchasing  a  set  of  wet 


COXSTRUCTIOX  AND  OPERATION  39 

batteries  the  following  points  ought  to  be  remembered: 
They  should  be  slop-proof  and  all  renewals  required 
should  be  easily  obtainable. 

The  jars  ought  to  be  as  substantial  as  possible  and 
constructed  so  that  chemicals  will  not  "creep"  over  the 
edge  of  the  jar  or  evaporate. 

When  space  allows  and  first  cost  is  not  of  utmost 
importance,  these  batteries  give  excellent  service  when 
used  for  either  system  of  ignition. 

The  advantage  of  this  type  of  batteries  is  that  the 
current  is  practically  constant  and  the  elements  usually 
zinc  and  copper  oxid ;  and  liquid  solution  may  be  re- 
newed, so  that  it  is  not  necessary  to  buy  a  new  set  of 
batteries  when  these  wet  cells  have  become  exhausted. 

Magneto  Ignition. 

A  magneto  is  a  machine  for  generating  an  electric 
current  by  employing  the  use  of  permanent  electric  mag- 
nets. Most  people  are  familiar  with  the  ordinary  horse- 
shoe magnet,  used  in  picking  up  needles,  etc.  This 


Magneto. 

same  sort  of  magnet  is  used  in  the  construction  of  the 
modern  magneto.  (See  illustration.)  The  shaft  is 
wound  with  copper  wire.  When  this  shaft,  called  an  arm- 
ature, is  revolved,  the  wire  rotating  between  the  ends  of 
the  magneto  is  influenced  by  them  and  an  electric  cur- 
rent is  set  up  in  the  wire.  This  current  can  then  be  led 
to  the  spark  coil  and  become  transformed  in  the  same 


40  MOTOR   BOATS: 

manner  as  that  of  battery  current.     Every  year  finds  the 
use  of  the  magneto  increasing. 

There  is  now  such  a  variety  of  these  machines  on  the 
market  that  if  care  is  taken  in  the  selection  of  the  ap- 
paratus and  proper  installation,  such  an  equipment  will 
give  perfect  satisfaction. 

The  electrical  requirements  of  the  jump  spark  and 
make-and-break  systems  are  not  the  same,  so  that  it  is 
necessary  to  construct  and  install  magnetos  adapted  to 
these  different  ignition  systems  somewhat  differently. 
The  best  magnetos  for  either  make-and-break  or  jump 
spark  systems,  however,  have  been  developed  to  a  point 
of  perfect  service. 

The  Dynamo  and  Storage  Battery  for  Ignition  and 
Lighting, 

The  storage  battery  system  consists  of  a  dynamo  and 
storage  battery  used  in  connection  with  any  standard 
electric  ignition.  It  can  also  be  used  to  supply  electricity 


Lackawanna  Electric  Light  Plant. 
(For  60  Lights.) 

for  a  number  of  low  voltage  incandescent  lamps  for  light- 
ing the  launch. 

The  storage  battery  may  be  used  singly  or  in  series 
of  several  numbers  depending  upon  the  capacity  or  dura- 


CONSTRUCTION  AND   OPERATION  41 

tion  of  current  required  to  operate  a  system  without 
re-charging.  The  dynamo  furnishes  the  electricity  to 
the  batteries  and  from  them  it  is  fed  to  the  ignition  and 
lighting  systems.  The  dynamo  is  usually  belted  to  the 
flywheel  of  the  motor  but  can  be  driven  with  friction 
wheel  or  spur  gears.  An  automatic  speed  governor  is 
generally  furnished  with  the  dynamo  and  serves  to  main- 
tain a  steady  volume  of  current  to  the  battery.  An  auto- 
matic switch  also  serves  to  break  the  dynamo  circuit 
when  the  batteries  have  been  charged  to  their  full 
capacity. 

This  system  furnishes  a  constant  and  steady  current 
and  obviates  the  necessity  of  replacement  or  renewals, 
as  with  dry  and  wet  batteries. 

It  is  hardly  possible  to  depend  upon  the  dynamo  alone 
without  any  batteries  to  start  a  motor,  unless  the  speed 
of  the  dynamo  can  be  made  high  enough  by  cranking  the 
motor  to  furnish  sufficient  strength  of  electricity  for  ig- 
nition. Therefore  it  is  advisable  to  use  some  source  of 
current  other  than  the  dynamo  to  start  the  motor. 

The  Timer   (or  Commutator)  for  Jump  Spark  Ignition. 

The  timer  is  a  mechanical  device  for  controlling  the 
time  for  ignition  of  the  gas  in  the  cylinder.  At  eight 
hundred  revolutions,  the  timer  in  a  three-cylinder  two- 
stroke  engine  is  called  upon  to  make  2400  perfect 
electrical  contacts  per  minute,  or  one  perfect  contact 
every  1/40  of  a  second,  consequently  it  is  necessary  to 
provide  a  segment  long  enough  (at  least  thirty-five  de- 
grees) to  care  for  the  rapid  movement.  Taking  the 
timer  of  the  well-known  Ferro  engine  as  an  example,  it 
is  tested  up  to  1800  revolutions,  5400  contacts  per  min- 
ute, without  missing.  It  has  an  adjustment  of  ninety 
degrees,  and  gives  economy  of  battery  power.  It  is 
driven  by  bronze  gear  meshing  with  a  similar  gear  on 
the  flywheel.  A  circuit  relief  button  is  in  a  convenient 


42  MOTOR  BOATS: 

position  for  stopping  the  engine  instantly,  by  simply 
pressing  with  the  thumb  while  the  hand  grasps  the  timer 
lever.  A  tight  bronze  cover  closes  the  contact  box.  The 
timer  spool  and  contact  box  are  occasionally  cleaned  with 
gasolene  and  a  daub  of  vaseline  oil  spread  on  the  spool 
for  lubricating  it.  It  is  only  necessary  to  unscrew  a  taper 
screw  less  than  one  half  a  turn  to  instantly  remove  all 
wearing  parts. 

Make-and-Break  vs.  Jump  Spark. 

The  make-and-break  or  mechanical  ignition  is  the 
original  device  that  was  used  with  the  marine  gasolene 
motor.  Although  the 'jump  spark  device  has  very  largely 
replaced  the  mechanical  ignition,  still  the  old  method 
has  several  features  of  advantage  over  the  jump  spark, 
which  make  it  most  commendable  for  the  commonly 
used  open  launch,  sueh  as  the  utility  boat  or  fishermen's 
craft.  The  make-and-break  igniter  by  virtue  of  its  low 
tension  electric  current,  which  is  supplied  direct  from 
batteries  or  a  dynamo  to  the  sparking  device,  is  not  sub- 
ject to  short  circuit  or  leakage  of  electricity,  as  is  the 
possibility  with  the  jump  spark,  due  to  its  transformed 
high  voltage  current,  where  the  latter  is  poorly  installed. 
The  damaging  elements  of  water,  moisture  and  even  salt 
air,  that  affect  the  unprotected  jump  spark  system,  have 
no  detrimental  action  on  the  unprotected  make-and-break 
system,  where,  with  the  motor,  it  is  exposed  to  weather, 
spray  and  moisture. 

It  is  a  universally  recognized  fact  that  the  jump  spark 
igniter  is  a  more  efficient  one  than  the  make-and-break, 
under  the  conditions  already  mentioned,  but  where  the 
jump  spark  is  not  adapted  and  the  right  care  and  pre- 
caution are  not  given  to  the  installation  and  operation  of 
it,  then  its  features  of  efficiency  must  give  way  to  some- 
thing better  and  more  reliable,  namely  the  mechanical 
spark. 


CONSTRUCTION  AND  OPERATION 


43 


Magneto  Connections. 
(See  Page  49.) 


44  t     MOTOR  BOATS: 

One  of  the  advantages  presented  with  the  jump  spark 
ignition  is  its  flexibility  in  timing  the  spark.  The  seeming 
difficulties  in  developing  this  feature  with  the  Ferro 
timing  device,  mentioned  above,  have  been  overcome  in 
that  an  early  or  late  spark  is  controlled  by  a  lever  in  oper- 
ating the  motor  either  left  or  right  hand  direction. 

Thus  it  is  that  many  engineers  advocate  the  make-and- 
break  ignition  where  it  is  to  be  placed  in  an  open  boat, . 
unprotected,  and  also  where  -it  is  more  desirable  to  the 
operator  to  be  confronted  with  simple  mechanical  ad- 
justments rather  than  a  more  complex  electrical  adjust- 
ment of  the  jump  spark  equipment. 

In  the  improved  Ferro  make-and-break  system  the 
spark  is  generated  in  the  cylinder  at  the  same  location 
as  with  the  jump  spark,  and  is  the  result  of  breaking  an 
electric  circuit  at  two  points  or  electrodes.  The  mechan- 
ism consists  of  the  sparking  device  set  in  a  brass  bush- 
ing. The  sparking  points  are  operated  by  a  trip  rod. 
The  timing  device  with  its  lever  is  so  constructed  as  to 
advance  or  retard  the  action  of  the  trip  rod  and  hence 
gives  a  late  or  early  spark. 

The  merit  of  this  mechanical  spark  lies  in  the  fact 
that  it  is  extremely  simple,  consisting  of  the  least  num- 
ber of  working  parts.  Its  mechanical  action  is  short  and 
consequently  capable  of  high  speed  with  the  motor  and 
accompanying  accuracy  in  the  time  of  required  ignition. 
All  the  movable  parts  are  constructed  of  case-hardened 
steel,  offering  the  greatest  strength  and  durability.  The 
electrode  points  are  of  nickel  steel,  free  from  any 
tendency  to  rust  and  always  maintaining  a  clean  electrical 
contact. 

The  Jump  Spark  System. 

The  high  tension  or  jump  spark  system  is  so  called 
because  the  spark  which  it  produces  has  a  voltage  suffi- 
ciently high  to  jump  a  fixed  air  gap.  This  system  has 


CONSTRUCT  10  X   AND  OPERATION  45 

no  moving-  parts  in  the  cylinder,  and  the  mechanism  is 
consequently  very  simple  and  not  liable  to  get  out  of 
order  by  wear.  On-  the  other  hand,  the  spark  current 
must  be  very  carefully  insulated,  since  metallic  contact 
is  not  necessary  for  a  leak,  and  dirt,  an  air  gap  of  l/±  inch 
or  less,  or  simple  moisture  about  the  igniters,  or  spark 
plugs,  will  permit  sufficient  leakage  to  destroy  the  spark. 
The  spark  plug  has  a  central  insulated  stem  surrounded 
by  a  porcelain  or  mica  tube  which  is  a  gastight  fit  in  a 
steel  shell  screwed  into  the  cylinder  wall.  At  the  inner 
end  a  spark  jumps  from  the  central  stem  to  an  extension 
of  the  steel  shell.  After  jumping  the  spark  gap  the  cur- 
rent grounds  itself  in  the  engine  and  completes  its  re- 
turn to  the  coil  through  the  primary  circuit.  The  effect 
of  the  action  of  the  trembler  or  vibrator  used  in  this  sys- 
tem is  to  induce  a  high  tension  current  in  the  secondary 
winding  of  the  coil  every  time  the  trembler  breaks  con- 
tact with  its  screw,  thereby  producing  a  stream  of  sparks 
at  the  spark  plug. 

Installation  of  Ignition. 

\Yiring  diagrams  are  usually  furnished  with  marine 
gasolene  engines  in  order  that  the  ignition  system  may 
be  properly  installed  and  the  'purchaser  should  preserve 
the  diagram  so  that  he  may  understand  the  system  in 
case  of  emergency.  There  are  several  points  that  should 
always  be  borne  in  mind.  For  instance,  in  a  high-tension 
system  the  heavily  insulated  secondary  wires,  that  lead 
from  the  coil  to  the  spark  plug  are  high  tension  wires 
conducting  a  high  voltage  of  electricity  and  the  utmost 
precaution  must  be  taken  to  avoid  short-circuiting  by  the 
wire  coming  in  contact  with  any  object  that  also  serves 
as  a  conductor  for  the  electric  current. 

All  portions  of  the  jump  spark  wiring  system  as  well 
as  the  batteries,  coil  and  plugs  must  be  well  protected 
from  water,  spray  and  even  moist  air,  for  they  all  have  a 


46 


MOTOR  BOATS: 


detrimental  effect  upon  it.  Nothing  but  the  very  best 
grade  of  wire  should  be  used,  particularly  for  the  sec- 
ondary current,  to  insure  satisfactory  results  at  all  times. 
It  is  essential  to  have  every  wire  connection  made  with 
a  clean  contact  and  rigidly  fastened  so  that  it  cannot 
work  loose  with  vibration  and  cause  failure  of  ignition 
perhaps  when  least  expected. 


Wiring   Diagram  For  Single   Cylinder  Engine. 
(Fairbanks,  Morse  &  Co.,  Chicago.) 

When  using  batteries  only,  it  is  well  to  have  two  sets 
of  five  or  six  each,  switching  from  one  to  the  other  alter- 
nately. This  allows  one  set  to  recuperate  while  the 
other  is  in  operation.  It  will  be  found  to  add  greatly  to 
the  life  of  the  batteries.  Where  a  motor  is  receiving 
steady  use,  it  is  advisable  to  install  a  magneto,  depending 
upon  the  batteries  to  start  with  only,  or  for  emergency 
in  case  of  possible  mishap  to  the  magneto. 

The  make-and-break  ignition  system,  although  some- 
what similar  to  the  jump  spark,  is  much  simpler  to  under- 
stand and  install.  The  wiring  diagrams  will  show  the 


CONSTRUCTION  AXD  OPERATION 


47 


most  satisfactory  method  used  with  batteries  or  the 
combination  of  a  dynamo.  The  same  arguments  in  favor 
of  this  combination  are  true  with  the  make-and-break 
system  as  they  are  with  the  jump  spark. 

There  are  no  high  tension  currents  of  electricity  with 
make-and-break  ignition,  but  nevertheless  care  should 
be  exercised  that  wires  do  not  cross  or  come  in  contact 
with  one  another  so  as  to  destroy  the  proper  course  of 
the  electricity.  The  coil  used  with  this  system  differs 
from  that  of  the  jump  spark  in  that  there  is  no  vibrator  to 
it.  The  construction  of  this  coil,  in  a  word,  is  a  spool  of 


Wiring  Diagram  With  Batteries  Wiring  Diagram  With  Batteries 
For  Two  Cylinders.  and  Magneto  For  Two 

Cylinders. 


Wiring  Diagram  With  Batteries  Wiring  Diagram  With  Batteries 
For  Three  Cylinders.  and  Magneto  For  Three 

Cylinders. 

wire  wound  around  an  iron  core.  It  serves  to  store  the 
electricity  for  each  successive  operation  of  the  igniting 
points,  thereby  imparting  greater  force  to  the  current, 


48 


MOTOR   BOATS: 


resulting  in  a  bright  hot  spark  in  the  cylinder.  The 
sparking  points  must  be  kept  free  from  accumulation  of 
burnt  carbon  or  it  will  interfere  with  a  good  spark,  if  not 
result  in  total  failure.  It  is  of  course  essential  to  keep 
the  mechanism  of  the  make-and-break  system  amply 
lubricated  with  the  frequent  application  of  a  first-class 
machine  oil. 


GROUND 
Double  Ignition  with  Single  Cylinder. 


"v 


DJ2Y  CELLS 
Connections  for  Remy  Magneto. 


CONSTRUCTION  AND  OPERATION  49 

High-Tension  Magnetos. 

Types  of  High-Tension  Magnetos — To  overcome  the 
mechanical  complications  of  the  low-tension  make-and- 
break  system  and  the  electrical  troubles  of  the  battery 
system,  the  high-tension  magneto  system  has  been  almost 
universally  adopted.  Depending  on  the  method  by  which 
the  low-tension  primary  current  is  stepped  up  into  the 
high-tension  current,  these  magnetos  may  be  classified 
into  three  general  groups. 

(1)  Dynamo  Type — The  dynamo 'type  of  magneto  is 
generally  driven  from  the  engine  by  a  belt  or  friction 
pulley. 

(2)  Transformer  Type — The  transformer  type  is  geared 
to  the  motor  so  that  the  armature  position  has  a  definite 
relation  to  the  piston.  A  primary  circuit  breaker  is  incor- 
porated in  the  magneto  that  breaks  the  primary  at  the 
end  of  the   compression   stroke.     The  low-tension  pri- 
mary current  generated  by  the  magneto  is  led  to  a  non- 
vibrating  spark  coil.     Only  a  single  spark  is  produced 
at  the  time  that  the  circuit  breaker  opens. 

(3)  True  High-Tension  Type — In  this  type  of  mag- 
neto the  armature  generates  high-tension  current  directly 
without  the  use  of  a  spark  coil. 

Direct  Current  Magnetos — The  direct  current  magneto 
is  commonly  used  on  stationary  engines.  As  the  speed' 
of  the  device  is  comparatively  high,  it  is  driven  with  a 
belt  or  friction  pulley  a  governor  being  used  to  keep  the 
voltage  constant.  It  can  be  used  for  charging  storage 
cells.  A  separate  circuit  breaker  or  timer  must  be  used. 
In  substituting  this  generator  for  a-  battery  it  is  only 
necessary  to  disconnect  the  batteries  and  reconnect  the 
same  two  wires  with  the  dynamo. 

Alternating  Current  Dynamos — Alternating  current 
dynamos  may  be  either  belt,  friction,  or  gear  driven  from 
the  motor.  This  type  is  not  installed  with  reference  to 
the  crankshaft  and  must  be  provided  with  a  separate 


so  'MOTOR  BOATS-. 

timer.  No  governor  is  necessary  with  the  alternating 
current  type,  as  the  generator  is  to'  some  extent  self- 
regulating.  This  class  cannot  be  used  for  charging  stor- 
age batteries.  It  is  placed  in  the  circuit  in  the  same  way 
as  the  direct  current  dynamo. 

True  High-Tension  Type — This  is  by  far  the  most 
common  type  of  high-tension  magneto  for  the  reason 
that  it  is  compact  and  self-contained.  It  requires  no  coil 
except  that  used  for  a  battery  auxiliary.  In  the  true 
high-tension  type  there  are  two  windings  on  the  arma- 
ture, a  primary  and  secondary,  the  secondary  like  the 
secondary  of  a  spark  coil,  being  composed  of  thousands 
of  turns  of  very  fine  wire.  The  primary  is  of  coarse  wire 
and  is  interrupted  by  a  circuit  breaker.  A  spark  is  pro- 
duced at  every  break  in  the  primary  circuit. 

The  outer  end  of  the  secondary  wire  is  connected  to 
the  high-tension  distributer  through  a  slip  ring  mounted 
on  the  armature  shaft.  The  distributer  is  driven  from 
the  armature  shaft  by  a  gear  so  that  it  revolves  at  cam- 
shaft speed.  This  type  is  geared  to  the  motor  in  a  defi- 
nite relation,  the  armature  shaft  running  at  exactly 
crankshaft  speed  in  the  two  and  four  cylinder  types,  and 
one  and  one-half  crankshaft  speed  in  the  case  of  the  six- 
cylinder  motor.  The  primary  circuit  breaker  is  then  so 
placed  that  it  opens  when  the  piston  is  very  near  to  the 
end  of  the,  compression  stroke,  thus  igniting  the  charge 
on  the  upper  dead  center. 

A  lead  from  each  spark  plug  is  brought  to  the  distrib- 
uter so  that  as  the  distributer  arm  revolves  it  comes  into 
contact  with  the  terminal  of  each  plug  in  the  correct  fir- 
ing order.  A  low-tension  lead  runs  from  the  breaker  box 
to  the  cutout  switch,  so  that  when  the  switch  is  closed 
the  primary  winding  of  the  armature  is  short-circuited, 
thus  stopping  the  motor. 

Advance  and  retard  in  this  type  of  magneto  is  had  by 
shifting  the  casing  of  the  circuit  breaker  back  and  forth 


CONSTRUCTION  AND  OPERATION  51 

so  that  the  primary  current  is  interrupted  earlier  or  later 
in  the  revolution. 


Typical  True  High-Tension  Type. 

In  the  accompanying  figure  is  shown  a  perspective 
view  of  a  true  high-tension  type  magneto,  the  magnets 
and  pole  pieces  being  omitted  for  the  sake  of  simplifying 
the  drawing.  The  armature  lies  between  the  pole  pieces 
and  magnets.  At  the  right  of  the  perspective  is  a  section 
through  the  armature  showing  the  actual  arrangements 
of  the  two  windings  on  the  armature.  The  shuttle  arma- 
ture of  "H"  form  is  indicated  by  H  in  both  views. 

The  body  of  the  armature  in  general  is  built  of  lamin- 
ated sheet  steel  to  prevent  the  generation  of  useless  cur- 
rents and  to  increase  the  magnetic  flux  through  the  wind- 
ing. The  primary  winding  is.  grounded  to  the  core  at  Y, 
and  is  then  given  several  turns  around  the  core  K,  the 
outer  end  of  the  winding  being  connected  to  the  bolt  2B 
at  M. 

From  the  point  M,  the  secondary  consisting  of  thou- 
sands of  turns  of  very  fine  wire  is  started.  The  inner 
end  of  the  secondary  being  connected  to  M  makes  the 
secondary  a  continuation  of  the  primary.  This  is  not 
shown  in  the  perspective  as  it  would  complicate  the  draw- 
ing, but  the  true  arrangement  can  be  seen  from  the  sec- 
tion at  the  right  in  which  J  is  the  primary  and  L  is  the 
secondary.  The  entire  series  of  winding  is  insulated 
from  the  core  by  the  insulation  indicated  by  the  heavy 
lines.  Primary  current  is  carried  to  the  circuit  breaker 
jaw  2A  and  the  switch  2D,  through  the  insulated  con- 
nection bolt  2B.  The  outer  end  of  the  high-tension  wind- 
ing is  carried  to  the  high-tension  collector  ring  E  by 
means  of  the  insulated  pin  2E.  A  brush  at  2B  carries 
primary  current  to  the  grounding  switch  2D,  which  when 
closed  stops  the  generation  of  high-tension  current. 


MOTOR  BOATS: 


A  primary  circuit  breaker  jaw  2 A,  connected  to  the 
primary  winding,  and  insulated  from  the  shaft,  revolves 
with  the  shaft  and  makes  intermittent  contact  with  the 
jaw  X  at  the  point  Z.  The  jaw  X  is  grounded  to  the 


///  WH/CH  C//S  T/J£  /=>/?/- 

/S 


Typical  True  High  Tension  Type  Magneto  Showing  Construc- 
tion and  Circuit  in  Diagrammatic  Form. 

shaft  and  revolves  with  it  so  that  the  two  contact  points 
are  always  opposite  to  one  another.  The  opening  and 
closing  of  the  jaws  is  accomplished  by  means  of  a  sta- 
tionary cam  which  acts  on  the  cam  roller  2C.  When  the 
contact  is  broken,  the  primary  circuit  is  opened  which 


CONSTRUCTION  AND  OPERATION  53 

gives  a  heavy  current  impulse  to  the  secondary  wind- 
ing. This  impulse  results  in  a  spark  at  the  plugs. 
The  spark  therefore  occurs  at  the  instant  when  the 
breaker  opens  the  circuit. 

By  shifting  the  breaker  housing  to  the  right  or  left  by 
means  of  lever,  the  breaker  jaws  open  sooner  or  later  in 
the  revolution  of  the  armature,  causing  the  advance  or 
retard  of  the  spark.  This  is  similar  to  the  effect  pro- 
duced by  rocking  the  housing  of  the  battery  timer. 

A  distributer  board  is  shown  in  the  perspective  which 
contains  the  metal  sectors  S-S2-S3-S4,  each  of  these  sec- 
tors being  connected  to  the  wires  1-2-3-4,  which  lead  to 
the  spark  plugs  in  the  cylinders.  These  sectors  receive 
high-tension  current  from  the  brush  T  contained  in  the 
revolving  distributer  arm  V,  each  sector  being  charged 
in  turn  as  the  arm  revolves.  The  distributer  board  is 
built  of  some  high  insulating  material  such  as  hard  rub- 
ber or  Bakelite,  and  is  shown  as  if  it  were  transparent  so 
that  the  armature  parts  may  be  seen. 

High-tension  current  from  the  secondary  winding 
passes  from  the  connection  2E  to  the  collector  ring  E, 
this  ring  being  thoroughly  insulated  from  the  frame  by 
the  hard  rubber  bushing  D,  shown  in  solid  black.  The 
high-tension  current  is  taken  from  the  collector  ring  by 
the  brush  C,  through  the  insulating  support  B,  and  to 
the  terminal  A.  From  A  the  current  passes  through  the 
bridge  P  to  the  distributer  arm  U  through  the  brush 
holder  Q  and  the  connector  V.  The  current  passes  to  the 
plugs  through  1-2-3-4,  and  the  plugs  being  grounded,  the 
current  returns  through  the  grounded  frame  to  the  arma- 
ture coil.  The  distributer  arm  V  is  driven  through  a 
gear  (not  shown)  from  a  pinion  on  the  armature  shaft  N. 

The  following  table  will  give  the  armature  speeds  for 
different  numbers  of  cylinders.  It  should  be  remembered 
that  in  all  cases  the  distributer  runs  at  camshaft  speed, 
and  that  there  are  as  many  distributer  sectors  as  there  are 


54 


MOTOR  BOATS: 


cylinders.     The  magneto  must  run  twice  as  fast  for  a 
two  cycle  engine. 

(Four-Cycle  Type  Motors  Only.) 


Ik 

Distributer 

No.  Cylinders 

Gear  Ratio 

Armature  Speed 

Note 

One 

No  Dist. 

Crankshaft  Speed 

T-^VO 

No  Dist. 

Crankshaft  Speed 

Three 

^tol 

24  Crankshaft 

Speed 

Four 

2  to  1 

Crankshaft  Speed 

*Five 

No  Dist. 

5/4  times  Crank- 

Rotary Motor 

shaft  Speed 

Dist.  on  Motor 

Six 

3tol 

\Y2  times   Crank- 

shaft  Speed 

*Seven 

No  Dist. 

1^4   times  Crank- 

Rotary  Motor 

shaft  Speed 

Dist.  on  Motor 

Eight 

4tol 

2  times   Crank- 

shaft Speed 

Single  Magneto 

Eight 

2tol 

Crankshaft  Speed 

Two   Magnetos 

(each  4  cyls.) 

*Nine 

No  Dist. 

9/4  times  Crank- 

Rotary Motor 

shaft  Speed 

Dist.  on  Motor 

fTen 

5tol 

2y2   times   Crank- 

shaft Speed 

Radial  Aero  Type 

Twelve 

6tol 

3  times   Crank- 

One Magneto  for 

shaft  Speed 

Twelve  Cyls. 

Twelve 

3tol 

\y2   times   Crank- 

Two Magnetos 

shaft  Speed 

(each  for  6  cyls.) 

*  Denotes  the  arrangement  used  with  rotary  engines  in  which 
no  magneto  distributer  is  used,  the  plugs  of  the  rotating  cylin- 
ders coming  into  contact  with  a  stationary  brush  held  by  the 
magneto.  The  magneto  is  of  the  single-cylinder  type. 

t  Denotes  a  radial  arrangement  of  cylinders,  all  cylinders 
being  stationary.  Seldom  used. 

Bosch  High  Tension  Magneto. 

The  Bosch  DU4  type  is  a  true  high  tension  magneto, 
the  armature  containing  a  primary  and  secondary  wind- 
ing. The  circuit  diagram  will  serve  as  a  guide  to  the  actual 
construction.  For  clearness,  the  armature  is  shown  in  side 
elevation,  while  the  distributer  and  circuit  breaker  are 
front  elevations.  The  primary  wiring  is  shown  by  solid 


CONSTRUCTION  AND  OPERATION 


55 


heavy  lines,  the  secondary  by  fine  solid  lines,  and  the 
grounded  circuit  by  dots  and  dashes. 

Since  the  secondary  winding  is  simply  a  continuation 
of  the  coarse  wire  primary  winding  it  is  shown  as  a 
single  coil.  The  high  tension  is  collected  at  the  left  of 
the  armature  by  means  of  a  collector  ring  and  brush,  the 
lead  from  the  upper  terminal  of  the  brush  being  con- 
nected to  the  safety  spark  gap  on  its  way  to  the  dis- 
tributer. The  distributer  brush  as  it  revolves  makes  suc- 
cessive contact  with  distributer  segments  1-2-3-4,  leads 
from  these  segments,  running  to  the  respective  spark 
plugs  1-2-3-4  shown  in  the  upper  lefthand  corner  of  the 
diagram. 

A  condenser  is  housed  with  the  armature  at  the  right 
whose  purpose  is  to  absorb  the  spark  at  the  breaker 


r 


Primary  winding 

Secondary  winding 

—  —     Frame 


Contact 
breaker  disk 


Bosch  High  Tension  Magneto  Circuit. 


points.  One  end  of  both  the  primary  winding  and  the 
condenser  is  grounded.  The  outer  shells  of  the  spark 
plugs,  the  frame,  and  the  armature  are  all  grounded  as 
will  be  seen  from  the  dot  and  dash  lines.  In  the  longi- 


56  MOTOR  BOATS: 

tudinal  section  the  high  tension  current  from  the  second- 
ary winding  is  led  to  the  high  tension  collector  ring  9. 
A  brush  10  pressing  on  this  ring  collects  the  current, 
and  through  the  spring  11.  the  bridge  12,  and  the  brush 
13,  it  passes  to  the  rotating  distributer  brush  or  arm 
15.  In  rotating,  the  brush  makes  successive  contact  with 
the  distributer  segments.  A  terminal  shown  projecting 
from  the  bridge  12  into  the  safety  spark  gap  housing  is 
placed  opposite  to  another  terminal  fastened  to  the  top 
plate  of  the  armature  tunnel.  This  gap  prevents  an  ex- 
cessive voltage  that  might  be  caused  by  a  loose  or  broken 
high-tension  connection. 

Primary  current  is  led  from  the  armature  to  the  cir- 
cuit breaker  through  the  insulated  connection  bolt  2,  an 
intermediate  connection  being  made  to  this  bolt  from 
the  condenser  8.  The  outer  end  of  the  bolt  2  is  connected 
to  the  interrupter  or  circuit  breaker  jaw  3,  an  insulating 
strip  4  separates  the  block  from  the  metal  of  the  frame. 
At  the  end  of  2  a  spring  controlled  brush  carries  cur- 
rent to  the  terminal  24  through  the  spring  26  and  the 
clip  25.  A  connection  from  24  is  led  to  the  grounding 
switch  whose  purpose  is  to  stop  the  engine.  .The  sup- 
porting block  27  is  insulated  from  the  clamp  23  which 
holds  the  distributer  cover  22  on  the  distributer  disk  16. 
A  hard  rubber  hub  14  carries  the  brush  15.  The  pro- 
longed shank  of  the  hub  14  rotates  in  the  bearing  at  the  ' 
left  of  the  hub,  the  bearing  being  thoroughly  insulated 
from  the  current  conducting  rod  that  runs  from  the 
brush  13  to  the  brush  15. 

The  end  of  the  primary  winding  is  connected  to  the 
plate  1  into  which  the  connecting  bolt  2  is  screwed.  This 
plate  is  insulated  from  the  frame  by  the  strip  of  hard 
rubber  shown  between  the  end  piece  and  the  condenser  8. 

Current  from  2  enters  the  breaker  block  or  jaw  3, 
which  On  referring  to  the  front  elevation,  will  be  seen  to 
carry  the  platinum  breaker  point  retained  by  screw  5. 


CONSTRUCTION  AND  OPERATION 


57 


These  parts  are  both  insulated  from  the  breaker  disk  4 
which  carries  the  rotating  parts.  A  contact  breaker  lever 
7  (grounded  to  the  frame)  carries  a  platinum  screw  29 
which  makes  contact  intermittently  with  the  first  plati- 
num point  5.  These  points  are  normally  forced  into  con- 
tact by  the  flat  spring  6.  It  should  be  remembered 

Oil 


FIG.  4. — Longitudinal  Section  Through   Bosch  Four  Cylinder 
High  Tension  Magneto. 

that  the  contact  block  3,  points  5  and  29,  the  lever  7  and 
the  spring  6  are  mounted  on  the  armature  front  plate  4 
and  revolve  with  it. 

Two  fiber  cam  disks  19-19  mounted  in  the  breaker 
housing  make  contact  with  the  toe  end  of  the  lever  7, 
causing  the  platinum  points  to  open  every  time  that 
the  end  of  the  lever  passes  the  cams.  As  this  is  a  shuttle 
armature  giving  two  current  impulses  per  revolution, 
there  are  two  cams  to  open  the  breaker  at  the  highest 
voltage  peak  of  each  impulse.  A  rocker  arm  20  is  con- 
nected with  the  breaker  housing  so  that  the  housing  and 
the  cams  can  be  rocked  for  advance  and  retard. 

The  brush  15  carried  in  the  distributer  arm  14  receives 


58 


MOTOR  BOATS: 


the  high  tension  current.  The  distributer  segments  con- 
nect with  plug  sockets  16  into  which  are  pushed  the 
plugs  or  spring  jacks  18  that  carry  the  high  tension  cables 
to  the  spark  plugs  in  the  cylinders. 

There  are  as  many  segments  and  plugs  as  there  are 
cylinders.  With  single  and.  double  cylinder  engines  there 
is  no  distributer,  the  high  tension  current  being  carried 


LL' 


Inductors  of  K.  W.  Magneto. 

directly  to  the  spark  plugs  from  the  high  tension  col- 
lector rings.  In  every  other  respect  the  construction  is 
the  same.  The  distributer  brush  is  driven  from  the 
armature  shaft  by  a  gear  and  pinion. 

Needless  to  say,  the  Bosch  magneto  must  be  geared 
or  chain  driven  by  the  engine,  since  there  is  a  positive 
relation  between  the  piston  position  of  the  engine  and  the 
time  at  which  the  circuit  breaker  opens  the  primary 
circuit. 

"K.  W."  Inductor  Type  Magneto. 

The  primary  winding  of  the  K.  W.  inductor  magneto 
occupies  the  space  between  the  two  revolving  inductor 


CONSTRUCTION  AND  OPERATION 


59 


masses,  and  gives  four  current  impulses  per  revolution. 
The  construction  of  the  K.  W.  system  is  shown  below 
in  which  I  and  I1  are  the  inductors  and  C  is  the  primary 
winding.  As  the  inductors  are  double  ended  and  at 
right  angles  each  inductor  cuts  the  magnetic  field  four 
times  per  revolution,  two  times  for  each  end. 

This  magneto  may  be  used  either  as  a  low  tension,  low 
tension  transformer  type,  or  as  a  true  high  tension  mag- 
neto. When  used  as  a  true  high  tension  type  the  usual 
circuit  breaker  and  high  tension  distributer  are  mounted 
directly  on  the  instrument. 


Longitudinal  Section  Through  K.  W.  High  Tension  Magneto. 

Like  all  magnetos,  the  true  high  tension  K.  W.  is  posi- 
tively driven  from  the  engines  through  gears  or  chain, 
and  a"s  there  are  four  impulses  per  revolution  instead  of 
two,  the  speed  relative  to  the  engine  is  half  that  given 
for  the  shuttle  type  armature. 

"K.  W."  High  Tension  Magneto. 

The  "K.  W."  high  tension  magneto  generates  high  ten- 
sion current  directly  without  the  use  of  a  spark  coil.  The 


60  MOTOR  BOATS: 

arrangement  of  the  coil  and  inductors  is,  practically  the 
same  as  in  the  case  of  the  low  tension  K.  W.  magneto 
except  for  the  fact  that  the  generating  coil  carries  both 
a  primary  and  secondary  winding. 

A  longitudinal  section  is  shown  above  in  which  16-16 
are  the  inductors  and  17-18  are  the  primary  and  second- 
ary coils  respectively.  A  hard  rubber  insulator  carries 
the  high  tension  lead  from  the  secondary  coil  to  the 
point  where  it  connects  with  the  bridge  21.  The  cur- 
rent from  the  primary  winding  is  led  to  the  circuit 
breaker  through  the  connectors  22,  25,  and  12,  the  final 
connections  coming  from  12  to  the  terminal  6,  and  then 
through  strip  5  to  the  breaker  jaws. 

High  tension  current  from  the  bridge  21  splits  two 
ways,  one  way  being  to  the  distributer  through  13,  and 
the  other  being  to  the  safety  sparks  gap  20.  Current 
enters  the  porcelain  cap  through  a  point,  and  if  a  suffi- 
ciently high  voltage  exists  it  jumps  across  the  gap  20  to 
the  point  mounted  on  the  condenser  case  19,  and  thence 
to  the  frame  and  ground.  A  condenser  19  is  connected 
across  the  primary  winding.  As  one  end  of  the  primary 
winding  is  grounded,  one  side  of  the  condenser  is  also 
grounded  to  the  condenser.  The  free  end  of  the  primary 
winding  is  closed  and  broken  by  the  interrupter  contacts. 

High  tension  current  from  the  lead  13  enters  the  dis- 
tributer by  the  way  of  the  brush  9, 


CHAPTER  VI. 

LUBRICATION   AND   COOLING   SYSTEMS. 

The  friction  between  moving  parts  of  a  machine  pro- 
duces heat  and  consequent  loss  of  energy.  Hence  to 
minimize  the  loss  and  prevent  wear  of  the  surfaces  in 
contact,  lubrication  is  necessary.  This  is  especially  true 
of  the  moving  parts  of  an  internal  combustion  engine,  and 
every  owner  of  a  gasolene  motor  finds  it  essential  to  see 
that  the  system  of  lubrication  performs  its  function  tho'r- 
oughly  under  all  conditions. 

The  best  lubricants  for  the  motor  boat  engine  and  re- 
versing gear  are  usually  specified  by  the  manufacturer, 
and  it  is  well  to  follow  the  advice  thus  given.  Owing 
to  the  fact  that  the  cylinder  walls  are  exposed  to  direct 
flame  on  the  explosion  stroke,  only  pure  mineral  oil 
of  high  fire  test  can  be  used.  Such  oil  is  known  as  "gas 
engine  oil,"  and  can  be  bought  in  different  viscosities  and 
qualities  to  suit  different  conditions.  The  oil  may  be  fed 
to  the  cylinder  walls  and  piston  in  various  ways,  but 
the  best  systems  are  those  known  as  the  splash  system 
and  the  mechanical  oiler  system.  In  the  former,  the 
crank-case  is  filled  with  oil  until  the  crank  ends  dip 
slightly  and  splash  the  oil  throughout  the  interior  of  the 
crank-case.  The  oil  is  supplied  to  the  crank-case  either 
by  sight  feed  oil  cups  or  by  a  mechanical  lubricator  run 
by  the  engine.  In  the  second  system  the  mechanical 
lubricator  feeds  oil  through  small  pipes  directly  to  the 
cylinder,  usually  on  the  side  against  which  the  piston 
presses  during  the  explosion  stroke.  The  crank-pin  bear- 
ings are  usually  oiled  by  splash,  and  the  main  crankshaft 


62  MOTOR  BOATS: 

bearings  receive  oil  either  by  splash  from  pockets  over 
the  bearings  inside  the  crank  case,  or  by  direct  feed  from 
a  mechanical  oiler.  The  main  shaft  bearings  may  be 
lubricated  by  oil  or  grease  according  to  design.  The  re- 
versing gear  is  generally  packed  with  grease,  mineral 
grease  being  preferable. 

As  state^,  oil  may  be  fed  to  the  pistons  either  drop  by 
drop  as  required,  or  by  internal  splash  in  the  crank-case. 
If  oil  cups  are  used  their  rate  of  feed  requires  constant 
watching,  as  it  is  greatly  affected  by  changes  in  tempera- 
ture, etc.  A  good  mechanical  oiler  is  very  reliable. 

A  lighter  oil  than  usual  may  be  used  in  cold  weather. 
The  Splash  System. 

Where  positive  pressure  oiling  systems  are  supplied, 
some  manufacturers  also  furnish  the  regular  "splash- 
feed"  system,  as  an  auxiliary  safeguard  against  careless- 


Crankshaft  Oil  Hole. 

ness  or  ignorance.  It  often  consists  of  two  wicks  in  the 
end  of  the  connecting  cap,  operating  on  the  crank-pin, 
which  constantly  feed  oil  to  this  bearing.  The  oil  which 
settles  down  into  the  bottom  of  the  crank-case  forrns 
a  pool  which  is  splashed  all  over  the  interior  by  the 
rapid  revolutions  of  the  crank,  and  thus  gives  the  sys- 
tem its  name.  This  system,  while  not  always  a  reliable  » 


CONSTRUCTION  AND  OPERATION  63 

one  for  general  oiling,  is  valuable  as  an  emergency  fea- 
ture, and  should  only  be  depended  on  as  such. 

There  are,  broadly  speaking,  four  vital  points  in  a  gaso- 
lene engine  which  must  positively  be  oiled — the  cyl- 
inder, piston,  crank-pin  and  crankshaft  main  bearings. 

When  the  "splash  system"  of  lubrication  is  used  it  is 
essential  to  keep  the  oil  level  such  that  the  cranks  dip 
into  it  very  slightly.  Too  much  oil  will  make  a  smoky 
exhaust  and  foul  the  igniters  with  soot  and  grease. 
Usually  a  sight-feed  or  mechanical  oiler  supplies  the 
crank-case,  but  it  may  be  necessary  to  add  extra  oil  from 
time  to  time.  When  the  oil  in  the  crank-case  gets  black 
it  should  be  thrown  away,  the  crank-case  interior  flushed 
with  kerosene,  and  the  engine  run  a  few  moments  to 
wash  the  bearings ;  after  which  the  kerosene  is  drained 
off,  fresh  oil  introduced,  and  the  engine  run  again  for  a 
minute  or  two  without  load  to  splash  the  oil  into  the 
bearings. 

The  crank-pins  may  receive  oil  by  simple  splash,  or  it 
may  be  fed  to  them  through  oil  ducts  in  the  cranks  from 
the  main  bearings  or  from  individual  supply  pipes.  The 
main  bearings  themselves  may  receive  oil  from  a  mechan- 
ical oiler,  from  individual  oil  cups,  or  from  pockets  over 
the  inner  ends  of  the  bearings,  into  which  oil  is  splashed 
by  the  cranks.  Whatever  arrangement  is  used  should  be 
well  understood  by  the  owner,  so  that  he  will  make  sure 
that  sufficient  oil  is  supplied. 

The  main  bearings  of  two-cycle  engines  are  frequently 
fed  with  grease,  the  object  being  to  prevent  air  leakage 
from  the  crank-case.  Grease  may  also  be  used  in  the 
main  bearings  of  a  four-cycle  engine  if  they  tend  to  run 
hot.  Spring  compression  cups  are  best  for  this  purpose. 
A  Typical  Oiling  System. 

The  plan  of  lubrication  adopted  in  single  and  multiple 
cylinder  Ferro  engines  of  the  most  recent  construction  is 
a  positive  pressure  sight-feed  oiling  system.  This  sys- 


64 


MOTOR  BOATS: 


tern,  it  is  claimed,  takes  nothing  for  granted  and  provides 
a  system  which  works  just  as  surely  as  the  engine  works, 
forcing  a  uniform  constant  supply  of  oil  to  every  bearing 
surface  in  the  exact  amount  for  each.  It  starts  auto- 
matically and  works  with  the  engine.  The  simplicity  of 
the  entire  device  is  notable.  The  oil  reservoir,  a  separate 
airtight  compartment,  is  cast  integral  with  the  crank- 
case.  A  short  tube  with  a  check  valve,  connects  the 


Ferro  3-cylinder  Engine. 


crank  chamber  to  the  reservoir.  At  each  revolution 
pressure  is  stored  in  the  reservoir,  and  thus  serves  to 
force  oil  up  to  the  sight-feed  distributer  through  a  feed 
tube.  From  the  bottom  of  each  sight-feed  valve,  an  oil 
tube  leads  directly  to  the  vital  part  of  each  bearing.  In 
a  single-cylinder  engine  there  are  four  sight-feed  valves 
and  tubes;  in  a  two-cylinder  engine,  six,  etc. 


CONSTRUCTION  AND  OPERATION  65 

The  system  of  distribution  is  as  follows :  The  tube 
leading  to  the  cylinder  conducts  the  oil  direct  to  its  in- 
side wall  at  a  point  in  line  with  the  hollow  piston  pin 
and  oil  grooves  of  piston.  The  oil  passes  through  the 
piston  pin  to  opposite  walls  of  cylinder  and  is  collected 
in  the  oil  grooves,  picked  up  by  the  piston  rings  and  dis- 
tributed by  the  up-and-down  motion  of  the  piston  to 
every  portion  of  the  rubbing  surface.  The  tube  leading 
to  each  main  bearing  cap  conducts  the  oil  through  the 
caps  to  the  rotating  crankshaft,  and  thence  through  holes 
drilled  from  main  bearing  portions  of  crankshaft  to 
crank-pin.  Each  ball  thrust  bearing  also  receives  its 
quota  of  oil  from  the  adjoining  main  bearing  cap.  Thus 
it  will  be  seen  that  every  vital  bearing  is  supplied  directly 
with  a  positive  feed  supply  of  lubricating  oil.  Each  sight- 
feed  valve  can  be  instantly  adjusted  to  deliver  a  "drop 
by  drop"  supply  to  its  respective  bearing.  As  an  addi- 
tional precaution  a  tube  is  led  to  the  carbureter,  where 
the  oil  is  vaporized  and  fed  to  all  interior  parts  of  the 
engine. 

The  regular  splash-feed  system,  as  above  described, 
is  also  supplied  with  Ferro  engines. 

COOLING  SYSTEMS. 

A  high  degree  of  heat  being  developed  in  the  cylinder 
of  a  gasolene  engine  by  the  combustion  of  the  fuel  mix- 
ture lubrication  is  not  sufficient  to  prevent  the  walls  of 
the  cylinder  from  becoming  overheated.  Unless  this 
tendency  is  counteracted,  the  result  will  be  the  cutting 
and  scoring  of  the  piston  and  cylinder  walls  where  they 
come  into  contact.  Hence,  it  is  absolutely  necessary  to 
remove  excessive  heat  in  the  metal.  There  are  two 
methods  commonly  used  for  this  purpose,  both  being  in 
successful  operation  at  the  present  time.  In  the  first  and 
most  common,  water  is  used  for  cooling  the  cylinder, 


66  MOTOR  BOATS: 

while  in  the  second  a  current  of  air  exerts  the  cooling 
influence. 

The  Water  Cooling  Method. 

The  water  method  consists  essentially  of  a  pump  and 
a  jacket  around  the  cylinder,  usually  cast  integral  with 
it.  This  jacket  forms  a  hollow  pocket  around  the  cyl- 
inder, through  .which  the  water  is  forced  and  kept  in 
constant  circulation,  thus  carrying  off  the  excess  heat  in 
the  metal. 

In  the  best  modern  practice  the  engine  design  is  such 
as  to  allow  for  independent  expansion  between  the  cylin- 
der and  its  jacket,  so  that  the  cylinder  may  expand  and 
contract  without  reference  to  the  jacket  or  barrel. 

The  pump  to  supply  the  cooling  water,  by  means  of 
a  cold  water  intake  and  seacock,  may  be  either  a  recipro- 
cating plunger  operated  by  an  eccentric  on  the  crank- 
shaft, or,  in  the  case  of  a  four-cycle  engine,  the  valve 
camshaft.  Rotary  pumps  are  also  sometimes  used. 

A  certain  amount  of  heat  is  required  for  the  success- 
ful operation  of  an  internal  combustion  engine  and  care 
must  be  taken  by  the  engine  designer  that  the  cooling 
system  does  not  remove  too  much  heat  from  the  cylinder. 
If  the  cylinder  becomes  overheated,  there  is  danger  of 
injury  to  both  piston  and  cylinder,  but  on  the  other  hand, 
if  too  much  heat  is  removed,  the  efficiency  of  the  engine 
will  be  lessened.  The  gasolene  engine  is  essentially  a 
heat  engine  and  in  the  cooling  system  a  happy  medium 
is  the  object  to  be  desired. 

The  Air  Cooling  Method. 

The  air  method  of  cooling  an  internal  combustion  en- 
gine consists  of  a  series  of  ribs  or  fins  arranged  around 
the  cylinder,  thus  presenting  a  large  radiating  surface 
over  which  is  usually  blown  a  constant  stream  of  air 
by  employing  a  rotary  fan  similar  in  design  to  the  or- 
dinary electric  fan.  For  marine  work,  where  water  is 


CONSTRUCTION  AND  OPERATION  6? 

at  hand,  it  is  far  more  practical  and  convenient  to  em- 
ploy it  as  a  means  of  cooling  the  cylinder  than  air.  The 
air-cooled  cylinder  is  more  liable  to  become  overheated, 
unless  some  further  means  is  employed  to  increase  the 
circulation  of  air. 


Air  Cooled  Cylinder. 

It  was  realized  long  ago  by  the  foremost  engine  build- 
ers that  the  cooling  problem  of  the  gasolene  engine  must 
receive  careful  study  or  power  and  efficiency  would  be 
sacrificed,  to  say  nothing  of  money  for  needless  repairs. 
Hence  the  former  idea  that  any  sort  of  water  cooling  ar- 
rangement would  suffice  so  long  as  it  provided  water  in 
contact  with  the  exterior  walls  of  the  cylinder,  is  fast 
passing  away.  In  the  best  modern  engines  the  proper  de- 
gree of  efficiency  is  secured  in  the  water  system  in  the 
simplest  and  most  direct  way,  the  cooling  water  pur- 
suing in  its  course  clean-cut  straight  lines,  free  from  air 
pockets. 

The  coolest  water  in  the  cylinder  jackets  is  near  the 
bottom.  The  hottest  part  of  the  cool  part  of  the  jacket 
is  where  the  exhaust  comes  from  the  engine.  At  that 
point  the  cold  water  supplied  by  the  pump  enters,  in  a 


68  MOTOR  BOATS: 

typical  modern  system,  and  passing  up  and  around  be- 
tween the  walls  of  the  cylinder  and  jacket,  discharges 
at  the  extreme  top  of  the  cylinder.  A  generous  sized 
concealed  trunk  main  delivers  the  water  to  the  cylinder, 
and  a  similar  concealed  duct  receives  the  discharge  from 
the  cylinder  jacket  and  carries  it  to  the  exhaust  con- 
denser, which  leads  the  exhaust  noiselessly  to  the  side 
of  the  boat  or  through  the  bottom. 

In  frosty  or  freezing  weather  particular  attention  must 
be  given  to  the  draining  of  all  water  jackets  and  chan- 
nels. This  can  be  done,  in  the  representative  system  re- 
ferred to  above,  by  simply  removing  the  water  drain  plug 
at  the  end  of  the  water  channel  under  the  crank-case 
and  loosening  the  vent  plug  in  top  of  the  cylinder.  If  de- 
sirable for  greater  convenience,  a  pet  cock  may  be  in- 
serted by  the  owner  in  place  of  the  channel  plug. 

Pumps. 

The  pump  is  a  very  important  part  of  the  motor  and 
should  be  specially  designed  to  supply  water  to  the  cyl- 
inder jacket,  in  as  steady  proportion  as  the  speed  of  the 
motor  may  require.  It  is  sometimes  a  slighted  feature 
of  marine  motors,  its  importance  not  being  always  prop- 
erly recognized,  but  the  tendency  of  modern  con- 
struction is  towards  perfection  of  this  feature  of  the  en- 
gine, and  very  satisfactory  pumps  are  furnished  by  some 
of  the  leading  engine-builders. 

The  illustration  shows  the  course  of  water  circulation 
in  the  Ferro  engine,  which  is  equipped  with  a  patent 
circulating  pump.  The  latter  consists  of  a  small  barrel 
with  stuffing-box,  in  which  a  hollow  piston  works,  driven 
by  an  eccentric,  whose  strap  is  pivoted  to  the  piston  by 
a  pin.  The  eccentric  is  bolted  to  the  crankshaft  by  a 
screw.  The  suction  nipple  is  connected  by  a  hose  with 
seacock  and  intake  passing  through  the  bottom  of  boat, 


CONSTRUCTION  AND  OPERATION 


69 


by   which    means   the   water   is   admitted   to   the   valve 
chamber. 

The  stem  of  the  suction  valve  slides  in  the  discharge 
valve.  Both  valves  drop  into  the  valve  chamber  and 
make  tight,  easy  fits  on  their  respective  seats.  The 
bonnet  which  closes  the  valve  chamber  permits  of  instant 
inspection.  The  pump  discharges  into  a  concealed  feed 


Water  Circulation— The  Ferro  Engine. 

main,  where  it  bolts  by  a  flange  to  the  engine  frame, 
A  trycock  drains  the  entire  pump.  If  grit  should  cut 
the  valve  seats,  it  is  a  simple  operation  to  grind  them  in 
by  applying  a  little  emery  and  oil  on  the  valve  seats 
and  turning  both  valves  in  place  by  the  wings  on  top 
of  the  discharge  valve. 

The  action  of  the  pump  may  be  facilitated  in  drawing 
the  water  from  the  seacock  or  intake,  by  placing  a  scoop 
over  the  opening  of  the  intake  pipe.  This  scoop  is  a 
crown-shaped  disk  with  two  long  openings  on  the  side 
that  catch  the  water  when  the  boat  is  moving  forward. 


CHAPTER  VII 
EXHAUST  DEVICES. 

The  noise  and  odor  of  the  exhaust  gases  escaping  from 
a  gasolene  motor  being  continuous  and  objectionable, 
some  device  is  necessary  to  deaden  them.  The  device  in 
universal  use  on  land  for  this  purpose  is  an  air  muffler 
and  for  marine  gasolene  engines  the  air  muffler  is  also 
often  used.  It  is  usually  made  in  the  form  of  a  cylindrical 
chamber  attachable  to  the  exhaust  pipe.  It  is  fitted  in- 


A   Common  Form  of   Marine  Air  Muffler. 

side  with  baffle  plates,  against  which  the  exhaust  gases 
expand  and  then  escape  into  the  air  at  the  open  end 
by  the  way  of  an  attached  pipe  leading  through  the  side 
of  the  boat  at  a  point  above  the  water  line. 

Water  Mufflers. 

The  air  muffler  serves  best,  however,  on  land,  for 
automobiles,  etc.  In  boats,  different  conditions  exist. 
On  account  of  the  well  known  condensing  action  of  water 
and  consequent  reduction  in  pressure  where  cool  water 
is  mingled  with  the  exhaust  gases,  it  is  possible  to  both 
silence  the  noise  and  increase  the  power  developed  by 
the  engine.  Besides,  as  the  water  is  being  pumped 
through  the  cylinder  jacket  constantly",  an  automatic 
feed  to  the  exhaust  pipes  may  be  had,  keeping  them  al- 
most cool  to  the  touch. 


CONSTRUCTION  AND  OPERATION  71 

The  first  form  of  muffler  consisted  of  a  water  jacket 
around  an  air  muffler  through  which  the  waste,  cooling 
water  was  led  and  then  piped  overboard.  Then  another 
method  was  tried,  namely,  running  some  of  the  water 
directly  into  the  exhaust  pipe,  between  the  engine  and 
the  muffler.  In  this  case  it  was  necessary  to  make  the 


A  Common  Form  of  Marine  Water  Muffler. 

muffler  water-tight,  while  the  air  muffler  is  not  water- 
tight. The  immediate  result  was  a  great  reduction  of 
noise  and  pressure  in  the  exhaust.  It  required  careful 
regulation  of  the  water,  also  a  drain  for  deposited  water 
in  the  muffler. 

The  Under- Water  Exhaust. 

The  under-water  or  submerged  exhaust  is  an  effective 
way  of  muffling  the  exhaust  noises,  but  it  must  be  in- 
stalled properly  to  be  a  success. 

A  submerged  exhaust  should  never  be  put  in  a  boat 
without  a  relief  valve  leading  to  a  free  opening,  so  that 
when  starting,  or  at  any  time  that  it  may  be  necessary, 
the  exhaust  may  be  turned  out  into  the  open  air. 

The  depth  below  the  water  and  the  location  of  the 
outlet  on  the  bottom  of  the  hull  are  dependent  greatly 
upon  the  general  lines  of  the  boat. 


72  MOTOR  BOATS: 

Choice  of  Exhaust  Devices. 

All  boat  owners  are  interested  in  the  question,  What 
method  of  discharging  the  exhaust  in  motor-boats  is 
most  efficient  in  reducing  the  noise  and  odor  without 
impairing  the  power  of  the  engine  or  interfering  with 
the  interior  arrangement  of  the  boat? 

This  question  was  asked  of  its  readers  recently  by  the 
popular  magazine,  Motor  Boating,  and  the  prize-win- 
ning answer  by  Mr.  L.  Kromholz,  of  New  York  City, 
was  as  follows: 

"The  choice  of  a  muffler  must  be  made  from  a  study 
of  the  circumstances  governing  each  case.  That  an  ar- 
rangement of  apparatus  gives  complete  satisfaction  on 
one  boat  does  not  necessarily  mean  that  it  will  be  equally 
successful  on  another. 

"For  open  launches  an  expansion  chamber  and  a  large 
pipe  leading  aft  to  the  stern  and  out  under  water  is  a 
good  and  simple  method.  The  difficulty  of  water  getting 
back  into  the  pipe  and  filling  the  cylinders,  can  be 
overcome  by  running  the  exhaust  pipe  in  a  straight  line 
(under  the  side  seats)  from  the  motor  to  the  outboard 
fitting.  This  will  be  well  above  the  waterline  and  have 
enough  pitch  so  as  to  drain  easily.  A  relief  cock  should 
be  fitted  to  assist  in  starting  the  motor.  The  loss  of 
power,  if  any,  will  be  slight,  in  fact  in  some  cases  .it  is 
claimed  more  power  can  be  obtained  with  the  submerged 
exhaust  than  without  it. 

"On  high  speed  runabouts  all  of  the  cooling  water 
from  the  motor  can  be  let  through  the  muffler,  but  the 
piping  must  be  in  a  straight  line  without  any  quick 
bends  where  the  water  is  likely  to  collect  and  choke  the 
exhaust.  A  completely  water-jacketed  exhaust  from  the 
motor  to  the  outlet  at  the  stern  is  an  efficient  device. 
The  straight  lead  aft  to  the  stern  will  cause  but  litttle 
back  pressure  if  the  pipe  is  of  good  size. 


CONSTRUCTION  AND  OPERATION  73 

"A  water-jacketed  muffler  or  one  with  the  cooling 
water  running  through  it  with  the  exhaust  outlet  under 
water  and  near  the  engine,  is  a  good  arrangement  for 
cabin  cruisers.  Another  way  would  be  to  wrap  asbestos 
around  the  exhaust  pipe  and  lead  it  under  the  seats  or 
berths  in  the  cabin,  under  the  flooring  in  the  cockpit 
to  the  muffler  in  the  stern  and  out.  In  this  way  the 
piping  would  have  a  fairly  straight  lead  with  no  sharp 
turns  and  would  not  interfere  with  the  accommodations 
to  any  extent.  Letting  the  exhaust  out  at  the  stern  is 
good  practice,  as  there  is  hardly  a  chance  of  the  odor  be- 
ing blown  over  the  occupants  of  the  cockpit. 

"On  the  larger  motor  boats  or  yachts  the  best  and 
most  popular  way  is  through  water-jacketed  mufflers 
in  a  false  funnel  or  stack.  But  while  a  stack  will  improve 
the  appearance  of  many  yachts  it  cannot  always  be  made 
a  thing  of  beauty. 

"Sharp  turns,  bends  or  ells  in  the  exhaust  pipe  should 
strictly  be  avoided  as  they  decrease  the  speed  of  the  boat 
a  great  deal." 

Another  experienced  boatman,  Mr.  J.  B.  Sadler,  of  the 
Navy  Yard,  Norfolk,  Va.,  also  writing  in  Motor  Boat- 
ing, advocated  the  under-water  method  of  muffling  as 
follows : 

"For  reducing  the  noise  and  odor  of  the  exhaust  in 
motor-boats  and  at  the  same  time  increasing  the  effic- 
iency of  the  motor,  the  submerged  exhaust  system  is 
without  an  equal. 

"By  this  system  the  exhaust  is  conducted  from  the 
motor  to  the  expansion  chamber,  which  must  be  located 
above  the  load  waterline  of  the  boat  and  from  thence 
to  a  special  fitting  or  nozzle,  located  in  the  bottom  or 
side  of  the  boat  below  the  waterline. 

"As  it  is  desirable  that  the  flow  of  the  exhaust  through 
the  exhaust  nozzle  be  continuous,  the  expansion  chamber 
must  be  placed  between  the  motor  and  the  nozzle,  and 


74  MOTOR  BOATS: 

should  have  at  least  six  times  the  cubic  capacity  of  the 
motor  cylinder. 

"Before  the  exhaust  passes  overboard  it  must  be 
cooled  and  contracted  to  its  original  volume,  otherwise 
the  contraction  will  take  place  beneath  the  boat  and  re- 
sult in  an  annoying  jar  tq  the  hull.  To  accomplish  this, 
the  general  practice  is  to  lead  a  part  of  the  circulating 
water  into  the  top  of  the  expansion  chamber  or  the  ex- 
haust pipe  leading  to  it,  but  as  the  circulating  water 
is  somewhat  heated,  it  is  better  to  pump  cold  water 
direct. 

"The  pipe  leading  from  the  expansion  chamber  to  the 
exhaust  nozzle  should  be  larger  than  the  exhaust  pipe, 
and  the  exhaust  nozzle  should  have  the  same  area  as  the 
enlarged  pipe. 

"The  exhaust  nozzle  should  point  aft  and  be  located 
away  from  the  propeller,  for  if  located  in  front,  it  tends 
to  slacken  the  speed  of  the  boat. 

"To  facilitate  starting  the  motor  and  prevent  water 
being  drawn  into  the  engine  cylinder  in  case  of  back- 
fire, a  three  way  cock  should  be  placed  in  the  exhaust 
line.  This  cock  should  be  so  arranged  as  to  have  the 
exhaust  opened  to  the  atmosphere  and  closed  to  the  sea 
when  starting  the  motor.  The  pull  exerted  on  the  ex- 
haust of  a  boat  equipped  with  the  submerged  exhaust 
system,  has  the  effect  of  increasing  the  speed  of  the 
engine.  In  some  cases  this  increase  has  been  as  much 
as  50  revolutions  per  minute." 


Intake  and  Exhaust  Header  For  a  3-cylinder  Engine. 


CHAPTER  VIII 
INSTALLATION  OF  ENGINES. 

As  a  rule,  it  may  be  said,  the  installation  of  a  marine 
gasolene  engine  is  a  comparatively  easy  matter.  By 
reference  to  the  diagrams  and  instructions  presented  in 
the  following  pages,  which  apply  to  well  known  engines 
of  typical  make,  the  amateur  will  be  able  to  install  an 
engine  properly  in  a  canoe,  rowboat,  launch,  flat-bottom 
boat,  sailboat  or  yacht  without  special  tools  or  expert 
experience.  These  instructions — or  those  furnished  by 
the  engine  builders  in  the  case  of  engines  not  referred 
to  here — should  be  read  with  care,  and  each  part  of  the 
work  should  be  done  in  the  order  named.  After  each 
part  has  been  done  the  work  should  be  examined  to  see 
that  it  has  been  done  properly  before  taking  up  the  next 
part. 

In  selecting  practical  instructions  for  installing  a,  few 
well-known  engines,  the  object  has  been,  not  to  show  any 
discrimination  in  favor  of  the  engines  mentioned,  but  to 
cover  by  actual  illustration  all  the  points  likely  to  arise  in 
installing  an  engine  of  any  make.  There  are  many  good, 
reliable  engines  in  the  market  besides  those  named^  in 
these  pages  and  the  power  boatman  has  a  wide  range  of 
choice.  No  matter  what  engine  he  may  select,  how- 
ever, he  will  find  among  the  instructions  given  below 
many  general  points  applicable  to  all  engines  alike — and 
these  are  the  points  most  essential  to  observe.  The  in- 
stallation features  peculiar  to  any  particular  engine  are 
always  clearly  indicated  by  the  manufacturer  or  sales 
agent. 


76 


MOTOR  BOATS: 


CONSTRUCTION  AND  OPERATION 


77 


It  is  impossible  to  get  satisfactory  results  from  your 
engine  unless  the  foundation  is  right  and  the  engine  is 
properly  installed.  The  foundation  should  be  so  con- 
structed as  to  take  up  the  thrust  and  distribute  the  en- 
gine vibration  over  a  large  part  of  the  bottom  of  the  boat. 
The  following  is  a  foundition  recommended  for  the 
Ferro  engine.  It  is  simple  and  easily  installed  and  yet 
fulfills  all  the  essentials  of  a  good  foundation: 

It  is  assumed  at  the  outset  that  the  skeg  or  shaft-log 
is  in  place  ready  to  receive  the  propeller  shaft.  Stretch 
a  string  so  that  it  passes  exactly  through  the  center  of  the 
shaft  hole  and  fasten  it  in  this  position,  having  the  for- 
ward end  a  little  in  front  of  where  you  plan  to  place  your 


Ferro  Special  on  Engine  Bed. 

engine.  This  string  will  be  c.bout  s/g  inch  higher  than  the 
level  of  the  top  of  the  engine  bed  (the  thickness  of  the 
crank-case  flange).  Another  method  is  to  place  a  piece 
of  gaspipe  in  the  shaft  hole,  making  it  long  enough  to 
reach  forward  of  the  engine  bed.  When  this  pipe  is  lev- 
eled up  it  will  give  you  almost  exactly  the  level  of  the 
engine  bed. 


78  MOTOR  BOATS: 

Get  out  two  fore-and-aft  pieces  (AA)  first.  All  the 
foundation  timbers  should  be  of  oak  if  possible,  or  other 
hard  wood  if  dak,  is  not  obtainable.  For  engines  below 
about  15  H.  P.  two-inch  stock  can  be  used,  but  pieces 
three  inches  thick  should  be  used  for  engines  over  15 
H.  P.  Lay  off  on  the  bottom  of  the  boat  the  position  of 
the  fore  and  aft  logs,  having  the  inside  width  between 
them  about  an  inch  less  than  the  width  between  the 
crank-case  holes  as  shown  on  the  engine  dimension  sheet. 

The  bottom  of  these  timbers  should  of  course  be 
shaped  to  conform  to  the  bottom  of  the  boat  in  the  posi- 
tion laid  off.  They  should  be  laid  on  top  of  the  ribs  and 
not  notched  out  to  receive  them.  The  height  of  these  fore- 
and-aft  timbers  can  of  course  be  determined  by  leveling 


Parts  of  Engine  Bed. 

up  a  straight-edge  on  top  of  the  string  or  pipe  and  meas- 
uring the  height  from  this  to  the  boat  ribs,  allowing 
about  y2  inch  in  using  the  wire  and  the  thickness  of  the 
pipe  in  using  that. 

The  distance  L-M,  the  engine  bed  proper,  is  of  course 
determined  by  the  length  of  the  crank-case,  and  must  be 
increased  when  using  the  reverse  gear,  as  shown  in  an 
illustration,  but  how  long  the  after-end  of  the  log  (M-N) 
should  be  must  be  determined  by  circumstances.  It  is  a 
good  plan  to  make  it  nearly  or  quite  as  long  as  the  for- 
ward distance  (L-M)  and  in  case  of  a  single-cylinder  en- 
gine it  will  do  no  harm  to  have  it  even  longer,  provided 
you  place  your  engine  in  such  a  position  as  to  make  this 
possible. 


CONSTRUCTION  AND  OPERATION  79 

Remember  a  single-cylinder  engine  requires  a  heavier 
bed  proportionately  than  a  multiple  cylinder  engine. 

Notch  out  underneath  the  forward  ends  of  the  fore-and- 
aft  timbers  about  two-thirds  of  their  height  to  receive  the 
forward  crosspiece  (B)  as  shown  in  the  diagram.  This 
crosspiece  should  be  cut  to  extend  the  extreme  width  of 
the  boat  and  should  be  carefully  shaped  to  fit  the  bottom 
of  the  boat  at  this  point. 


Reverse  Gear  on  Engine  Bed. 

Another  crosspiece  (D)  ties  together  the  after  ends  of 
the  fore-and-aft  timbers,  being  notched  out  at  both  ends 
to  receive  them.  This  piece  can  run  the  whole  width  of 
the  boat  and  should  be  full  height  and  shaped  to  conform 
to  the  bottom  of  the  boat.  In  installing  engines  of  15 
H.  P.  or  over,  it  is  also  well  to  add  a  crossbrace  between 
the  fore-and-aft  timbers  just  forward  of  the  pump  and 
of  as  great  height  as  possible  and  yet  give  plenty  of  clear- 
ance. Crosspieces  should  be  about  \l/2  inches  thick  for 
the  smaller  engines  and  2  inches  for  the  larger  ones. 

After  all  the  timbers  are  got  out  they  should  be  nailed 
down  temporarily  and  the  engine  and  shaft  put  in  place 
to  test  the  foundation  and  see  if  it  is  of  the  proper  height 


80  MOTOR  BOATS: 

and  slant  so  the  shaft  will  be  in  line  when  the  engine  is 
in  place.  If  ribs  do  not  come  under  the  engine  bolt  holes, 
put  in  extra  ones  that  will,  so  you  can  bolt  through  them. 
If  this  test  shows  the  foundation  to  be  right  or  nearly  so, 
the  logs  may  >be  bolted  down  as  shown  in  the  diagram. 
Note  that  all  crosspieces  are  bolted  through  the  keel  and 
the  fore  and  aft  pieces  bolted  through  rib  and  planking 
at  intervals  of  every  other  rib.  In  no  case  should  bolts 
be  fastened  through  the  planking  only,  as  this  will  work 
the  planking  loose.  Put  good-sized  washers  coated  with 
white  lead  under  the  boltheads  on  the  bottom  of  the  boat 
so  as  to  prevent  possibility  of  leakage.  Note  that  the 
crosspiece  is  lagged  to  the  fore  and  aft  pieces  in  front  and 
the  middle  crossbrace  lagged  through  them  from  each 
side. 

With  the  foundation  thus  fastened  in  place,  the  engine 
is  now  ready  to  be  installed.  The  final  lining  up  should 
be  done  when  the  boat  is  in  the  water,  for  then  it 
changes  its  alignment  somewhat.  If  your  boat  has  no 
skeg,  but  an  outboard  bearing,  place  your  inboard  stuf- 
fing-box on  the  shaft,  but  don't  fasten  it  in  place  until 
you  have  lined  up  your  engine  and  shaft.  But  if  your 
boat  has  a  skeg,  put  your  stuffing-box  outside  in  place 
first  and  see  whether  the  shaft  turns  freely  before  it  is 
fastened  to  the  engine.  If  not  loosen  the  box  and  pack 
around  it  until  the  shaft  turns  freely,  then  screw  the  box 
in  place.  The  hole  in  the  shaft  log  should  be  *4  mcn 
larger  than  the  diameter  of  the  shaft.  Fill  with  white 
lead  between  the  stuffing-box  and  its  seat. 

After  putting  the  engine  in  place  fasten  half  of  the 
flange  coupling  to  the  propeller  shaft  and  hold  this  up 
against  the  flange  coupling  on  the  end  of  the  engine 
crankshaft.  Note  whether  the  two  halves  come  together 
evenly  all  the  way  around.  If  not,  move  the  engine  side- 
ways or  pack  up,  or  cut  away  under  one  end  as  the  case 
may  be  until  four  strips  of  paper  placed  between  the  two 


CONSTRUCTION  AND  OPERATION  81 

parts  of  the  coupling  on  opposite  sides  are  held  with  even 
tension  as  the  coupling  is  pressed  together.  Now  bolt 
down  the  engine  in  the  four  corners  and  try  the  strips  of 
paper  again.  If  all  are  held  evenly,  bolt  the  engine  down 
permanently;  if  not  change  the  position  of  the  engine  as 
before  until  the  right  position  is  found. 

This  done,  take  the  spark  plugs  out  of  the  cylinders 
and  note  how  much  force  is  required  to  turn  the  engine 
over.  Then  bolt  the  coupling  together  and  again  try 
turning  the  engine  over.  It  should  turn  as  freely  as  be- 
fore. This  is  important.  The  engine  must  turn  as  freely 
when  coupled  to  the  propeller  shaft  as  when  uncoupled. 

TILLER 


ALLOW  AT L£AST 


KEEL  OUTSIDE. 

STUFFING  BOX. 

RUDDER 

Propeller  Installation. 

If  it  does  not,  something  is  out  of  line  and  must  be 
changed  or  serious  loss  of  power  and  perhaps  worse 
trouble  will  result.  Unbolt  your  coupling  and  go  care- 
fully over  your  alignment  again  as  described  above. 
Pack  the  stuffing-box  between  the  nut  and  body  with 
hemp  or  candle  wicking  soaked  in  grease  and  screw  up 
just  tight  enough  to  stop  water  leak  but  not  enough  to 
bind  the  shaft. 

To  Install  a  Reversible  Propeller — Before  connecting 
shaft  to  engine  coupling  locate  the  lever,  quadrant,  thrust 
and  clamp  collars  and  inside  stuffing-box.  Place  quad- 
rant with  pin  towards  the  engine.  Allow  space  between 

6 


82 


MOTOR  BOATS: 


fork  and  stern  bearings  for  moving  the  lever  forward  to 
unlock  the  header  when  pin  is  removed  from  the  forward 
end  of  quadrant.  On  long  shafts  place  bearings  every 
five  feet  along  the  tubing.  Be  sure  the  shaft  does  not 
bind  in  any  way.  Use  grease  between  shaft  and  sleeve 
and  in  blade  joints.  Place  the  reverse  lever  in  a  vertical 


OPENING 
Water  Intake  Installation. 

position  with  tips  of  blades  square  with  shaft.  Then 
securely  bolt  clamp  collars  against  center  thrust  collar. 
The  blades  will  then  have  the  same  pitch  whether  full 
lead  ahead  or  reverse.  To  remove  the  blades,  take  out 
the  pin  in  the  forward  end  of  the  quadrant,  moving  lever 
forward  until  the  blades  are  unlocked  from  fork,  then  un- 
screw the  blades  from  the  hub. 

Bore  the  hole  for  your  water  intake  in  such  a  place  that 
the  piping  between  the  pump  connection  and  intake  will 
have  no  sharp  turn  in  it,  and  never  reduce  size  of  this 
pipe.  A  short  piece  of  hose  can  be  used  as  a  joint  for 
flexibility,  but  we  would  caution  you  against  making  this 
hose  connection  too  long,  as  you  will  have  leaks  and 
pump  trouble.  As  good  an  intake  connection  as  any  is  to 


CONSTRUCTION  AND  OPERATION 


83 


take  a  short  piece  of  gas  pipe  threaded  to  take  a  lock 
nut  on  the  inside  and  one  on  outside  of  planking.  Pack 
the  lock  nuts  inside  and  out  with  two  or  three  turns  of 
candle  wick  soaked  in  white  lead.  It  is  well  to  connect  a 
cut-out  valve  to  the  intake  connection.  Outside  this  in- 
take connection  fasten  the  scoop,  putting  the  fine  wire 
screen  inside  and  turning  the  scoop  opening  forward  in 
fastening  it  to  the  bottom  of  the  boat. 

Installing  Lamb  Engines. 

The  following  instructions  for  installing  the  well 
known  Lamb  engines,  built  by  the  Lamb  Boat  &  Engine 
Company,  of  Clinton,  Iowa,  are- remarkable  for  clearness 
and  conciseness  and  contain  many  excellent  hints  ap- 
plicable to  the  installation  of  engines  in  general : 


Lamb  4-cylinder  24  H.  P.  Engine. 

Keelson  and  Bilge  Keelsons — In  constructing  a  power 
boat,  a  keelson  is  usually  notched  over  the  ribs  and  bolted 
to  the  keel.  In  addition  to  this,  bilge  keelsons  or  stringers 
are  recommended,  one  on  either  side,  and  running  nearly 
parallel  to  the  keelson. 


84  MOTOR  BOATS: 

These  keelsons  also  should  be  notched  to  fit  over  and 
securely  fastened  to  the  ribs  and  planking.  The  keelsons, 
coming  under  the  motor  foundation  timbers  and  over  a 
number  of  ribs,  distribute  the  strain  over  a  large  area 
and  contribute  largely  to  the  stiffness  of  the  structure. 

Shaft  Hole — The  shaft  hole  should  be  bored  the  size 
given  in  table  of  motor  dimensions  in  the  catalogue,  ta- 
king care  that  it  is  of  such  a  pitch  or  angle  that  the  pro- 
peller will  be  entirely  submerged,  and  that  no  part  of 
motor  bed  or  flywheel  will  come  in  contact  or  touch  the 
inside  of  boat  aside  from  the  foundation  timbers. 

With  properly  constructed  deadwood,  there  is  no  shaft 
hole  lining  needed  except  where  the  stuffing-box  is  placed 
on  the  inside  of  the  boat.  With  the  last  named  arrange- 
ment a  brass  or  iron  tube  may  be  used,  the  stuffing-box 
fastened  to  the  inboard  end  and  the  stern  bearing  to  the 
outboard  end. 

The  shaft  hole  being  bored,  stretch  a  fine  line  through 
the  center  of  it ;  fasten  the  outboard  end  to  a  stick  nailed 
to  the  stern  of  the  boat ;  make  the  other  end  fast  inside 
of  boat ;  go  over  the  line  carefully  and  see  that  it  is  in  the 
exact  center  of  hole  throughout  its  length,  and  if  the 
shaft  hole  has  been  properly  bored,  a  plumb-bob  held  be- 
side the  line  should  point  to  the  center  of  the  keelson, 
provided  the  boat  sits  level. 

The  face  of  the  stern-post  must  be  absolutely  smooth 
and  at  exactly  right-angles  with  the  line  which  has  been 
stretched  where  the  center  of  the  shaft  should  be. 

Foundation — In  the  table  of  motor  dimensions  in  the 
catalogue  see  distance  from  the  center  of  the  shaft  to  the 
bottom  of  floor  flanges.  This  distance  being  known,  the 
foundation  timbers,  which  should  be  of  good  sound 
oak,  should  be  securely  fastened  to  keelsons  at  the  given 
distance  from  the  line,  and  at  the  same  pitch  or  angle  as 
the  line. 


CONSTRUCTION  AND  OPERATION  85 

These  foundation  timbers  may  run  either  athwart  ship 
or  fore  and  aft ;  in  either  case  they  must  be  securely  fast- 
ened to  every  timber  and  plank  over  which  they  pass. 
The  table  of  motor  dimensions  gives  all  necessary  meas- 
urements, but  it  is  well  to  check  your  measurements 
over  when  you  receive  the  motor. 

Placing  Motor — Place  the  motor  on  the  foundation  at 
the  proper  position  fore  and  aft,  and  in  line  with  the 
center  of  the  shaft.  The  shaft  now  being  in  place,  com- 
pare the  faces  of  flange  couplings  and  see  that  their  faces 
come  together  fairly.  The  least  variation  at  this  point, 
if  allowed  to  remain,  will  cause  undue  friction  and 
heating. 

With  motor  securely  bolted  down  and  faces  of  flanges 
on  the  couplings  coming  up  perfectly  fair,  you  may  feel 
reasonably  sure  your  motor  and  shaft  are  in  line.  This  is 
important. 

Stern  Bearing  and  Stuffing  Box — Bolt  the  stern-bear- 
ing to  stern-post  with  a  film  of  white  lead  between.  See 
that  the  shaft  turns  perfectly  free  after  the  stern-bearing 
is  fastened  to  place.  If  it  binds  the  shaft,  it  would  indicate 
that  the  face  of  the  stern-post  is  not  exactly  at  right- 
angles  on  the  shaft  and  must  be  dressed  off  until  the  shaft 
works  free. 

If  a  log  is  used,  the  inside  stuffing-box  is  bolted  to  the 
inboard  end,  after  having  squared  the  end  the  same  as 
described  for  the  stern-post.  If  no  log  is  used,  insert  a 
sleeve,  one  end  of  which  screws  into  the  stern-bearing, 
the  sleeve  being  long  enough  to  extend  into  the  boat  far 
enough  to  admit  of  the  stuffing-box  being  screwed  on  the 
inboard  end. 

Piping — Use  care  in  cutting  threads  on  all  pipe  so  that 
they  will  make  up  tight,  using  white  lead  on  all  joints 
of  water  pipe  and  soap  on  all  gasolene  connections. 

Make  all  pipe  runs  as  direct  as  possible,  avoiding  el- 
bows and  bends.  Water  pipes  should  be  all  brass  where 


86  MOTOR  BOATS: 

the  boat  is  used  in  salt  water,  but  for  fresh  water,  com- 
mon iron  pipe  will  answer. 

For  the  sea-cock  or  intake  to  the  pump,  the  pipe  should 
have  long  running  thread  cut  on  the  end  intended  to  go 
through  the  planking.  The  hole  should  be  bored  through 
the  bottom  of  the  boat  small  enough  so  that  the  pipe  will 
screw  tight  into  planking.  Have  a  lock-nut  both  inside 
and  out  after  the  pipe  is  screwed  through  the  planking  far 
enough  to  admit  of  a  full  tread  on  the  lock-nut  outside. 
Put  a  few  turns  of  white-leaded  candle  wicking  under 
the  lock-nuts  and  screw  down  firmly,  tacking  a  dish 
screen  over  the  end  of  pipe  to  keep  all  foreign  matter  out 
of  the  check  valves. 

A  stop-cock  should  be  placed  just  inside  of  the  boat 
that  the  flow  of  water  may  be  regulated  to  suit  condi- 
tions. It  is  also  advisable  to  place  a  tee  just  above  the 
stop-cock,  taking  the  water  from  the  side  of  the  same 
with  a  plug  in  the  end.  In  case  of*  pipe  getting  clogged, 
the  plug  may  be  removed  and  a  small  rod  of  wire  used  to 
clean  same. 

The  discharge  from  the  water-jacket  overboard  should 
be  above  the  water  line  if  possible  and  should  be  fastened 
as  described  above  for  the  sea-cock  pipe;  all  water  pipe 
to  be  no  smaller  than  the  openings  in  or  out  of  the  motor 
for  same,  and  larger  will  do  no  harm. 

Gasolene  Pipe — Gasolene  pipe  should  be  of  copper,  tin, 
brass  or  lead,  never  iron,  and  should  be  run  from  the  tank 
to  the  carbureter  as  directly  as  possible  along  the  keelson. 

See  that  the  gasolene  pipe  is  thoroughly  cleaned  before 
making  up,  as  a  very  small  amount  of  dirt  or  scale  will 
clog  the  carbureter. 

Gasolene  Tank — The  gasolene  tank  should  be  placed 
as  high  up  in  the  bow  of  the  boat  as  possible  so  that  the 
gasolene  will  have  sufficient  head  to  flow  to  the  car- 
bureter good  and  strong. 


CONSTRUCTION  AND  OPERATION  87 

The  gasolene  tank  should  have  a  strainer  over  the  out- 
let opening,  inside  of  the  tank.  A  hole  should  be  cut 
through  the  deck  to  correspond  to  the  filling  plug  in  the 
tank  and  the  gasolene  should  be  thoroughly  strained 
when  filling  the  tank.  Chamois  skin  makes  the  best 
strainer  as  no  water  will  pass  through  it.  The  tank  must 
be  securely  fastened  in  the  boat  to  avoid  straining  of 
joints  in  the  gasolene  pipe,  should  the  tank  shift. 

Exhaust  Pipe — Either  of  two  styles  of  mufflers  is  fur- 
nished with  Lamb  engines.  The  one  most  to  be  desired 
is  of  the  automobile  type,  and  can  only  be  used  on  boats 
with  a  fixed  roof.  The  mufflers  are  light  and  are  securely 
fastened  to  the  roof,  the  exhaust  pipe  from  the  motor 
running  up  through  the  roof  to  the  muffler,  with  sheet- 
iron  hood  running  from  the  motor  to  and  through  the 
roof,  covered  by  a  cone  to  shed  water.  This  hood  should 
be  two  inches  larger  than  the  exhaust  pipe,  thereby  fur- 
nishing a  one-inch  air  space  around  the  exhaust  pipe, 
which  is  sufficient  to  carry  off  the  heat  from  the  exhaust 
pipe. 

The  other  style  is  the  stern  muffler,  to  go  under  the 
stern  deck,  with  outlet  from  muffler  running  out  from 
either  side  of  the  stern.  This  style  of  muffler  necessitates 
the  running  of  the  exhaust  pipe  under  the  floor  of  the 
boat  to  the  stern,  connecting  to  the  muffler  and  then  out 
as  previously  described. 

Where  this  type  of  muffler  is  used  it  is  advisable  to 
admit  a  small  amount  of  the  discharge  water  from  the 
water-jacket  into  the  exhaust  pipe  to  keep  it  cool.  There 
should  be  a  valve  placed  in  the  water  pipe  to  the  exhaust 
pipe  that  the  amount  may  be  regulated,  as  too  great  an 
amount  of  water  in  the  exhaust  pipe  tends  to  choke  same 
and  to  check  the  speed  of  the  motor. 

Batteries — Lamb  motors  are  regularly  furnished  with 
two  sets  of  dry-cell  batteries.  These  should  be  placed  in 


88  MOTOR   BOATS: 

a  dry  place  in  the  boat  and  connected  as  shown  by  the 
wiring  chart  accompanying  each  motor.  Where  dyna- 
mos or  magnetos  are  used,  one  set  of  batteries  are  cut 
out  and  the  generator  wired  in  their  place.  A  dynamo 
or  generator  will  give  much  better  satisfaction  if  used  in 
connection  with  a  storage  battery. 

Wiring — If  there  is  one  thing  more  important  than 
another  in  motor  installation,  it  is  the  wiring,  which 
should  be  done  carefully  and  well.  All  wires  should  be 
visible  and  above  floor  if  possible;  for  instance:  We 
will  explain  the  method  of  wiring'  the  Lamb  4-cylinder 
4-cycle  motor.  The  wiring  chart  fully  describes  or  shows 
the  manner  of  connecting  batteries  to  the  spark  coil  and 
from  the  spark  coil  to  the  motor;  the  circuit-breaker  or 
timer  has  four  binding  posts  marked  1,  2,  3,  4.  These 
indicate  the  post  to  run  the  primary  wires  to  for  each 
cylinder,  for  instance :  Taking  one  end  of  the  coil  as  No. 
1,  run  the  primary  wire  from  this  end  coil  to  the  binding 
post  marked  (1),  also  secondary  wire  from  same  coil 
to  the  spark  plug  on  the  top  of  No.  1  cylinder  on  the 
motor. 

Run  wires  on  numbers  2,  3,  and  4  cylinders  in  the  same 
manner.  Having  completed  the  wiring  as  described,  re- 
move spark  plugs  from  the  cylinder  heads  and  lay  them 
on  top  of  the  cylinder,  so  that  they  make  contact  the 
same  as  if  they  were  in  place.  Now  beginning  with  No. 
1  cylinder,,place  piston  on  the  upper  center  after  having 
completed  the  compression  stroke.  Be  sure  it  is  the  com- 
pression stroke. 

Now  set  your  timer  to  spark  at  this  point  and  you 
should  have  spark  on  No.  1  spark  plug.  Then  try  the 
next  cylinder,  which  should  be  No.  3 ;  be  governed  by  the 
numbers  stamped  on  the  timer  for  the  sequence  in  firing. 

After  timing  each  cylinder  perfectly  your  motor 
should  start  readily. 


CONSTRUCTION  AND  OPERATION  89 

Installing  a  Mianus  Motor. 

(Mianus  Motor  Works,  Mianus,  Conn.) 
If  the  motor  is  to  set  in  a  boat,  allow  at  least  three 
inches  under  the  rim  of  flywheel  so  as  to  give  the  hand 
plenty  of  clearance  in  starting.  If  possible  set  the  motor 
so  that  there  will  not  be  over  one  and  one-half  inches 
pitch  to  foot  of  propeller  shaft.  After  the  motor  is  set 
turn  the  carbureter  connections  so  that  it  will  stand 


Mianus  Single  Cylinder  Engine. 

plumb,  otherwise  the  valves  may  not  work  freely.  All 
circulating  pipes  for  salt  water  should  be  of  brass.  The 
gasolene  feed  pipe  should  be  of  brass  or  copper.  Great 
care  should  be  exercised  in  making  up  the  connections 
for  the  gasolene  supply,  so  that  there  will  be  no  pos- 
sibility of  a  leak.  Make  up  all  threaded  joints  with 
shellac  or  common  bar  soap  and  solder.  Exhaust  pipe 
is  usually  of  galvanized  iron.  Avoid  placing  the  ex- 


90 


MOTOR  BOATS: 


haust  pipe  nearer  than  one  inch  to  any  woodwork — two 
inches  would  be  better.  Cover  if  possible  with  asbestos. 
Set  the  gasolene  tank  above  the  level  of  the  carbureter ; 
three  or  four  inches  is  enough.  In  a  boat  the  tank  is 
nearly  always  in  the  bow,  as  tnat  is  the  highest  point. 
For  auxiliary  installation  we  would  recommend  placing 
the  tanks  aft  on  deck  under  the  lockers  or  seats  if  pos- 
sible; this  will  avoid  the  necessity  of  running  the  gaso- 
lene pipes  through'  the  cabin  or  other  inclosed  parts  of 
the  boat.  In  connecting  the  gasolene  supply  use  two 
stop-cocks,  one  at  the  tank  and  one  at  the  engine,  also 
use  two  unions  in  the  same  way;  then  either  tank  or 
motor  may  be  removed  without  removing  the  other.  All 
air  must  be  forced  out  of  the  gasolene  pipe  before  motor 
can  be  started.  All  water  connections  should  have  stop- 
cocks or  seacock  with  aircock  to  drain  all  piping.  Be 
sure  that  the  inlet  has  a  suitable  screen  to  cover  the 
opening  to  keep  out  dirt  and  other  foreign  matter.  Water- 
jacket  and  pipes  must  be  kept  drained  in  cold  weather 
when  not  in  use. 


Mianus   Motor   Installed   With   Two   Stuffing-Boxes   A   A. 


CHAPTER  IX 

OPERATION  AND  CARE  OF  ENGINE. 

There  are  three  important  points  that  must  be  care- 
fully looked  after  before  any  gasolene  engine  will  operate 
successfully : 

First :  You  must  be  sure  that  your  engine  receives  a 
good  spark. 

Second :  You  must  know  that  your  engine  receives  a 
proper  amount  of  gas. 

Third :  You  must  see  that  all  the  bearings  are  properly 
oiled. 

Some  marine  engines  are  so  simple  that  they  are 
claimed  to  be  as  easy  to  run  as  an  ordinary  sewing  ma- 
chine. The  amateur  will  have  no  trouble  in  learning 
how  to  operate  one  of  them  perfectly  if  he  follows  in- 
structions carefully. 

But  don't  make  your  first  attempt  thinking  that  you 
know  all  about  it  and  can  make  the  engine  run  at  the 
first  turn ;  for  if  you  do,  you  are  likely  to  be  disappointed 
and  might  get  discouraged. 

Remember,  that  the  makers  have  assured  you  that  you 
can  learn  to  operate  their  engine  without  much  trouble ; 
and  you  can.  But  you  must  be  patient,  careful,  sensible, 
self-reliant,  and  follow  the  makers'  instructions  closely. 
If  you  don't  get  results  at  first,  don't  condemn  the  en^ 
gine  or  blame  the  builders  until  you  know  that  either  the 
engine  or  the  builders  are  to  blame.  Every  engine  has 
probably  been  run  for  hours  on  its  own  power  before 
leaving  the  factory  and' if  it  does  not  run  for  you,  look 
for  the  trouble  in  the  way  you  operate  it,  for  there  you 
will  most  likely  find  it. 


92  MOTOR  BOATS: 

Don't  listen  to  advice  or  suggestions  from  self-styled 
experts,  and  don't  experiment  or  "monkey"  with  the 
engine. 

If,  after  fair  trial,  you  are  unable  to  make  the  engine 
run,  write  the  builders  and  tell  them  all  about  your 
trouble,  and  they  will  then  offer  such  suggestions  as  are 
needed.  They  won't  let  you  fail,  and  you  won't  fail  if  you 
do  your  part.  Just  use  sense,  study  the  instructions  and 
keep  trying.  You  will  soon  get  the  knack  of  running  the 
engine  and  then  all  will  be  pleasant. 

The  Lamb  Four-Cycle  Engine. 

The  following  instructions  for  the  operation  and  care 
of  Lamb  engines  will  be  found  interesting  by  many 
owners : 

Starting  and  Running  Motor — Fill  the  gasolene  tank. 
Fill  the  oil  tank  and  oil  all  moving  parts  of  the  motor. 
Oil  the  clutch  through  the  plug-hole  in  the  top  of  the 
case.  Turn  the  motor  over  several  times  and  see  that 
everything  works  free.  Throw  the  clutch  lever  in  neutral 
or  center  position.  Open  the  valves  in  the  gasolene  pipe 
at  the  tank  and  at  the  carbureter  to  be  sure  gasolene  flows 
freely. 

It  is  advisable  on  first  starting  the  motor  or  in  cold 
weather  to  prime  the  motor  by  putting  a  small  amount  of 
gasolene  in  each  of  the  priming  cups  and  letting  it  into 
the  inlet  valves  by  means  of  the  cock  below  the  cup. 

Set  your  lead-changer  so  that  the  motor  fires  just  after 
passing  the  center  to  avoid  kicking  back.  Open  the 
throttle  valve  on  mixer  about  half  way.  Throw  the  switch 
on  the  batteries.  Stand  on  the  carbureter  side  of  the 
motor  and  throw  the  top  of  the  flywheel  towards  you. 

After  the  engine  gets  to  running  regulate  the  speed 
of  the  motor  by  the  throttle  lever  on  the  carbureter  and 
by  the  lead-changer.  See  that  the  sea-cock  is  open  and 
that  water  is  coming  out  of  the  over-flow  pipe.  See  if 
pump  is  working  by  means  of  pet-cock. 


CONSTRUCTION  AND  OPERATION 


93 


Gasolene  Regulation — Just  enough  gasolene  should  be 
used  to  give  the  motor  its  maximum  speed,  the  carbureter 
being  automatic.  The  gasolene  flow,  if  adjusted  at  slow 
speed,  should  be  right  at  all  speeds. 

The  varying  heights  of  gasolene  in  tank  will  make  no 
difference  in  the  flow  of  gasolene,  as  this  is  controlled  by 
a  float  in  the  chamber  of  the  carbureter. 

Advancing  Spark — After  throwing  in  the  clutch,  the 
speed  of  motor  may  be  increased  25  per  cent  by  advancing 
spark  to  fire  ten  to  fifteen  degrees  before  center.  This  is 


Connecting  Rods — The  Lamb  Engine. 
Piston  and  Rings — The  Lamb  Engine. 

variable  according  to  speed  of  motor.  The  higher  the 
speed  of  the  motor  the  more  lead  the  motor  will  stand 
without  pounding. 

Loss  of  Compression — May  be  caused  by  leaky  valves 
or  by  the  piston  packing  rings  becoming  gummed. or  in- 
active by  the  use  of  poor  cylinder  oil.  An  occasional 
dose  of  kerosene  will  be  found  helpful  in  the  latter  case. 

When  everything  is  perfectly  tight,  it  will  be  found 
hard  to  turn  motor  over  with  relief  valves  closed. 

Inlet  and  Exhaust  Valves — The  inlet  and  exhaust 
valves  are  both  mechanically  operated,  and  may  be  easily 
removed  for  regulating  or  inspection  as  follows :  Loosen 
the  nuts  above  the  saddle,  turn  the  saddle  slightly  from 


94  MOTOR  BOATS: 

under  the  nuts  and  the  valve  caps  may  be  lifted  off ;  then 
compress  the  valve  spring  and  slip  up  the  spring  collar 
and  remove  spring;  the  spring  and  collar  will  then  drop 
off  and  the  valve  can  be  lifted  out  of  the  chamber.  If 
necessary  to  regrind  valves,  use  a  fine  grade  of  emery 
and  oil,  using  a  screw  driver  in  the  slot  in  top  of  valve 
to  revolve  same. 

Igniters — These  are  of  the  jump  spark  type  in  the 
Lamb  engine.  In  running,  the  motor  should  ignite  ten 
to  fifteen  degrees  before  the  crank  reaches  the  upper  dead 
center,  in  order  that  the  charge  may  be  properly  fired  by 
the  time  the  power  stroke  starts. 

In  starting  the  motor,  the  ignition  should  not  occur 
until  the  motor  has  passed  dead  center,  otherwise  the 
motor  will  kick  back,  and  starting  will  be  difficult. 

To  fulfill  the  foregoing  conditions,  it  becomes  neces- 
sary to  provide  a  means  of  regulating  the  time  of  ignition. 
This  in  the  Lamb  engine  is  provided  for  in  a  movable  cir- 
cuit-breaker, controlled  at  the  front  of  the  motor  by  a 
handle  with  a  notched  segment. 

Ignition  Troubles — If  after  reasonable  trial  the  motor 
refuses  to  start,  set  the -motor  on  a  dead  center  and  place 
circuit  breaker  or  timer  in  position  to  spark,  then  throw 
on  the  switch  to  see  if  the  vibrator  works  or  buzzes.  Try 
all  cylinders  in  same  manner. 

Testing  Spark — Remove  the  spark  plugs  from  the  cyl- 
inders. Lay  them  on  top  of  the  cylinder  so  that  the  body 
of  the  plug  is  ground  the  same  as  if  they  were  in  place  in 
the  cylinder  head.  Now  test  each  one  for  a  spark  by 
turning  the  motor  from  point  to  point  of  contact  or  by 
using  screw-driver  or  other  instrument  across  the  points 
on  the  circuit-breaker. 

Vibrator — Adjust  the  vibrator  until  you  obtain  a  good 
hot  spark  and  the  vibrator  has  a  good  strong  buzz.  If 
the  vibrator  works  and  no  spark  shows  across  the  points 
of  the  spark  plug,  it  would  indicate  that  the  spark  plug 


CONSTRUCTION  AND  OPERATION  95 

was  short-circuited,  caused  by  either  water,  soot,  oil  or 
broken  insulation,  cracked  porcelain,  etc. 

Spark  Plug — Use  a  small  brush  to  keep  the  points  of 
spark  plugs  clean  and  free  from  scale,  soot,  oil,  etc. 
Broken  or  cracked  insulation  must  be  replaced  by  new 
parts. 

Timer — The  interior  or  moving  parts  should  be  kept 
well  oiled. 

Wiring — Go  over  the  wires  carefully  and  see  that  all 
connections  are  tight  and  no  bare  wires  come  in  contact 


Reverse  Clutch- — The  Lamb  Engine. 

with  other  wires  or  parts  of  the  motor.  Wires  should  not 
pass  through  bilge  water ;  all  bare  wire  and  joints  must  be 
wound  with  tape. 

Batteries — Must  be  kept  in  a  dry  place  and  allow  no 
tools  of  any  kind  to  lie  on  top  of  batteries,  as  they  will 
become  short-circuited  and  useless  in  a  short  time. 

Motor  Knocking — May  be  caused  by  the  flywheel  be- 
ing loose,  too  early  ignition,  one  or  more  cylinders  miss- 
ing, mixture  too  light,  (not  enough  gasolene).  Motor 
cylinders  heating  caused  by  stoppage  of  water  circulation. 

Reverse  Clutch — Where  the  motor  is  furnished  with  a 
reverse  clutch,  the  mechanism  consists  of  six  spur  gears, 
two  friction  clutch  rings,  and  a  retaining  casing.  The 
internal  clutch  ring  is  securely  keyed  to  the  propeller 
shaft  and  forms  the  forward  motion  to  the  shaft. 


36    '  MOTOR  BOATS: 

Going  Ahead — A  spur  gear  is  rigidly  secured  to  the 
crankshaft  and  engages  the  four  long  spur  pinions  that 
extend  to  and  engage  the  spur  gear  that  is  secured  to  the 
wheel  shaft.  The  after  clutch  ring  or  external  one  is 
secured  to  the  motor  bed  by  lugs,  and  by  friction  engages 
the  casing.  When  the  forward  or  internal  ring  is  fric- 
tionally  connected  by  means  of  a  sliding  cone  to  the  ca- 
sing, the  casing  with  its  contained  gears  (the  gears  re- 
maining inoperative),  carries  the  propeller  shaft  with  it 
in  rotation  with  the  crankshaft. 

At  Rest — If  neither  clutch  ring  is  connected  to  the  ca- 
sing, the  resistance  of  the  propeller  in  the  water  holds  it 
idle  while  the  motor  revolves  and  the  gears  in  the  casing 
run  idle. 

Going  Astern — Should  the  after  or  external  clutch  be 
frictionally  connected  to  the  casing  the  casing  is  held  still 
and  the  crankshaft  gear  engaging  the  four  long  spur 
pinions  and  these  in  turn  with  spur  gear  on  the  propeller 
shaft,  cause  the  propeller  shaft  to  revolve  in  an  opposite 
direction. 

Adjusting  Clutches — It  is  necessary  that  both  clutch 
rings  be  so  adjusted  as  to  hold  the  full  power  of  the 
motor. 

Slipping — Slipping  of  forward  or  internal  clutch  is 
indicated  by  motor  racing  and  the  casing  heating  over  the 
clutch  ring. 

Adjusting — In  adjusting  the  forward  clutch,  loosen 
the  lock  nuts  on  the  adjusting  screws  on  the  clutch  dogs, 
and  adjust  the  screws  that  engage  on  the  cone ;  care  must 
be  taken  that  each  screw  be  adjusted  the  same.  Neglect 
of  this  will  cause  the  clutch  to  slip  even  though  it  may 
be  very  hard  to  get  the  cone  under  the  points  of  the 
screws. 


CHAPTER  X 
HYDROPLANES. 

Buoyancy. 

When  a  solid  object,  such  as  a  block  of  wood,  is 
thrown  into  water  it  will  continue  to  sink  until  the 
weight  of  the  water  displaced  is  equal  to  the  weight  of 
the  block.  When  this  occurs  a  position  of  equilibrium  is 
reached  which  is  called  "floatation,"  and  the  body  will 
rest  with  more  or  less  of  its  mass  above  the  surface. 
Should  the  weight  of  a  solid  block  be  more  per  cubic 
foot  than  the  weight  of  a  cubic  foot  of  water  it  is  evident 
that  no  such  point  of  equilibrium  will  be  found  and  that 
such  a  body  will  sink  until  the  bottom  is  reached.  As  an 
example  we  will  work  out  the  following  problem  to  show 
the  relations  between  weight  and  floatation : 

A  box  10  feet  long,  4  feet  wide,  and  3  feet  high,  weighs 
200  pounds.  How  far  will  it  sink  in  water  weighing  62.5 
pounds  per  cubic  foot? 

The  water  displaced  will  be  equal  to  the  weight  of 
the  box,  and  will  have  a  volume  of  200  -^-  62.5  =  3.2  cubic 
feet.  To  immerse  the  box  1  foot  will  displace  10x4x1  =  40 
cubic  feet  of  water,  so  that  the  weight  of  the  box  will 
sink  it  3.2-:- 40  =  0.08  foot,  or  very  nearly  1  inch.  Con- 
sider that  a  boy  weighing  100  pounds  is  placed  in  the 
box  causing  the  total  weight  to  be  300  pounds.  The 
volume  of  water  displaced  will  be  300  -=-  62.5  =  4.8  cubic 
feet,  and  the  depth  of  immersion  will  be  4.8  -f-  40  =  0.12 
foot  or  1.44  inches. 

From  the  above  it  will  be  seen  that  the  supporting  force 
must  be  equal  and  opposite  to  the  weight  of  the  floating 
body.  This  is  known  as  the  "buoyant  force"  or  buoyancy 


98  MOTOR  BOATS: 

of  the  water.  Since  the  weight  of  a  cubic  foot  of  water 
varies  with  the  temperature  and  with  the  amount  of  salt 
in  solution  it  is  evident  that  a  boat  will  float  higher  in 
cold  sea  water  than  in  warm  fresh  river  water.  If  the 
depth  of  immersion  is  an  important  factor  in  the  design, 
such  as  would  be  the  case  with  craft  intended  for  use  in 
shallow  streams,  the  items  listed  above  must  be  taken 
into  account.  By  knowing  the  volume  of  the  hull  and  its 
weight  it  is  possible  to  locate  the  water  line  accurately 
by  the  above  method. 

While  iron  and  steel  are  much  heavier  per  volume  than 
water  it  is  possible  to  construct  metal  boats  by  having 
the  volume  of  displacement  increased  to  such  a  point  that 
the  weight  per  cubic  foot  of  hull  is  less  than  the  weight  of 
a  cubic  foot  of  water.  By  the  judicious  distribution  of 
material  it  is  possible  to  have  a  metal  boat  that  is  lighter 
per  cubic  foot  of  displacement  than  an  equivalent  wood 
hull,  and  therefore  one  that  will  ride  less  deeply  in  the 
water. 

Displacement  Boats. 

All  ordinary  boats  are  supported  in  the  water  by  the 
weight  of  the  displaced  water  on  the  principles  outlined 
above.  To  distinguish  them  from  a  class  of  racing  craft 
known  as  "Hydroplanes,"  such  boats  are  commonly 
called  "displacement"  boats  from  the  method  of  floata- 
tion. 

Hydroplanes. 

When  a  flat  plane  surface  is  held  at  an  angle  near  the 
surface  of  the  water  and  is  pushed  rapidly  forward,  the 
water  is  forced  downwards  by  the  inclined  surface  and 
an  upward  pressure  is  brought  against  the  plane  by  the 
impact  of  the  deflected  stream.  By  suitably  arranging 
the  angle  of  the  plane  and  the  forward  speed  it  is  possible 
to  derive  enough  upward  force  to  suspend  the  entire 
weight  of  a  hull  and  its  passengers  without  the  aid  of  the 
displacement  buoyancy.  Such  support  of  course  is  only 


CONSTRUCTION  AND  OPERATION  99 

possible  when  the  boat  is  moving  at  a  considerable  speed, 
and  therefore  the  boat  must  have  sufficient  buoyancy 
to  float  the  load  when  at  rest.  A  boat  which  is  supported 
by  the  reaction  of  a  moving  stream  of  water  against  an 
inclined  surface  is  known  as  a  "Hydroplane." 

Hydroplanes  are  almost  invariably  built  as  speed  boats 
or  for  racing  and  at  present  hold  all  speed  records  in  the 
gas  driven  field.  They  are  quite  different  in  construction 
from  the  usual  motor  boat,  are  exceedingly  light  and 
heavily  powered.  The  bottoms  are  broad  and  flat  with 
the  greater  part  of  the  weight  arranged  in  the  stern  so  as 
to  maintain  a  particular  angle  with  the  surface  of  the 
water.  At  full  speed,  the  reaction  of  the  water  on  the 
inclined  bottom  causes  them  to  skip  over  the  surface 
much  on  the  principle  of  a  skipping  stone.  The  bow  and 
fore  part  of  the  hull  stand  well  out  of  the  water  with  the 
greater  part  of  the  weight  carried  by  the  after  portion  of 
the  bottom. 

As  the  hydroplane  at  speed  is  only  barely  immersed, 
the  area  of  skin  friction  is  reduced  to  a  minimum  as  is 
also  the  energy  required  to  split  the  water.  By  reduc- 
ing these  losses  it  has  been  possible  to  considerably 
exceed  a  speed  of  60  miles  per  hour.  When  at  full  speed 
it  has  been  possible  to  see  "daylight"  between  the  water 
and  the  hull  for  a  distance  of  fully  two-thirds  of  the 
length  of  the  boat.  As  the  speed  drops  the  boat  gradu- 
ally sinks  deeper  and  deeper  into  the  water  until  it 
reaches  its  full  displacement  depth  when  at  rest. 

Owing  to  the  small  amount  of  surface  resting  on  the 
water  and  to  the  absence  of  keels  it  is  not  stable  when  at 
speed  and  is  very  likely  to  "skid"  sideways  after  the 
manner  of  an  automobile  on  a  wet  pavement.  It  is  not 
adapted  for  use  on  rough  choppy  water  since  the  impact 
of  waves  of  different  heights  not  only  disturb  the  fore  and 
aft  equilibrium  but  also  are  likely  to  strike  the  bow  and 
cause  the  plane  to  "stub  its  toe"  and  probably  to  cause 


100  MOTOR  BOATS: 

it  to  dive  to  the  bottom.  Because  of  this  instability  in 
the  fore  and  aft  balance  many  hydroplanes  have  taken 
a  sudden  dive  to  the  bottom  carrying  passengers  and  all 
with  them.  For  this  reason  the  average  hydroplane  is 
not  a  safe  proposition  for  the  inexperienced  motor-boat 
operator. 

Being  of  an  unusually  fragile  construction,  any  degree~of 
rough  water  is  likely  to  break  the  back  of  the  plane.  In 
many  cases  a  500  or  600  H.  P.  engine  is  carried  in  a  hull 
with  only  a  A  or  i/^-inch  mahogany  shell  so  that  when 
the  weight  of  the  motors,  the  operators  and  the  fuel  are 
considered  it  will  be  seen  that  there  is  not  a  large  factor 
of  safety  even  with  the  most  careful  operation  and  under 
the  most  favorable  conditions  of  water. 

Probably  the  most  important  single  factor  in  the  con- 
struction of  a  hydroplane  is  the  balance  or  the  manner 
in  which  the  weights  of  the  motors,  fuel,  etc.,  are  dis- 
tributed. With  a  proper  weight  distribution,  proper 
propeller  and  plenty  of  power  almost  any  displacement 
boat  can  be  made  to  act  as  a  hydroplane  with  more  or 
less  success,  but  with  improper  balancing  even  the  most 
efficiently  designed  hydroplane  hull  will  perform  indiffer- 
ently or  not  at  all.  Again,  the  angle  which  the  bottom 
makes  with  the  surface  is  a  factor  and  this  varies  not  only 
with  the  loading  but  with  the  speed.  The  proper  assem- 
bling of  a  hydroplane  plant  is  therefore  not  a  rule  of  the 
thumb  proposition  but  a  matter  of  experience  and  judg- 
ment— and  still  further,  a  matter  of  individual  experiment 
with  each  hull.  Even  the  most  experienced  designers  and 
constructors  of  planes  are  occasionally  compelled  to  dis- 
card a  hull  and  consign  it  to  the  scrap  heap  through  their 
inability  to  exactly  forecast  these  conditions. 

In  gradually  starting  from  rest,  the  planing  bottom 
makes  only  a  slight  angle  with  the  surface  of  the  water, 
the  weight  of  the  engine  and  fuel  being  placed  at  the 
rear  so  as  to  point  the  nose  slightly  upwards.  As  the 


CONSTRUCTION- AND  OZERATIOX  101 

speed  increases,  the  increased  pressure  due  to  the  impact 
of  the  water  raises  the  nose  still  further  and  increases  the 
angle.  As  the  angle  increases  the  center  of  pressure,  or 
the  effective  point  of  application  of  the  stream,  moves 
steadily  toward  the  rear,  thus  reducing  the  leverage  of 
the  engine  and  fuel,  and  finally  causes  the  forward  weight 
to  overcome  that  in  the  rear.  This  of  course  now  tends 
to  reduce  the  angle  after  a  certain  speed  is  reached  which 
is  fairly  correct  balance  since  an  excessive  angle  causes 
loss  in  the  water  and  elevates  the  bow  so  that  the  wind 
resistance  is  high. 

These  losses  due  to  excessive  angles  and  wind  resis- 
tance are  especially  noticeable  at  the  higher  speed  now 
reached  since  the  power  required  to  overcome  them  varies 
as  the  cube  of  the  speed.  As  the  sustaining  effect  is  now 
great,  the  angle  can  be  reduced  to  a  certain  extent  and 
still  maintain  sufficient  support.  By  properly  adjusting 
the  weights,  etc.,  the  angle  can  be  made  to  adjust  itself  to 
the  proper  degree  at  any  speed,  so  that  the  losses  are  at  a 
minimum  and  the  power  most  effective.  The  movement 
of  the  center  of  pressure  is  the  uncertain  factor  in  arrang- 
ing the  balance,  and  can  be  compared  in  effect  with  the 
movement  of  the  support  under  a  "teeter  board."  If  we 
know  the  point  of  support  at  any  one  instant  we  can  eas- 
ily arrange  the  weights  to  balance,  but  as  the  center 
moves  irregularly  and  not  at  all  according  to  any  known 
law,  the  matter  is  not  an  easy  one  to  solve.  This  is  further 
complicated  by  the  effect  of  differently  shaped  planes  on 
the  pressure  movement,  a  slight  curve  giving  widely 
different  results  from  those  produced  by  a  flat  plane. 

In  general,  a  hydroplane  may  be  defined  as  a  boat  in 
which  the  power  is  used  to  lift  the  boat  out  of  the  water, 
to  reduce  the  resistance,  as  well  as  to  drive  her  forward. 

In  the  faster  hydroplanes,  the  power  plant  is  divided 
into  two  groups  with  twin  screws,  the  "Oregon  Kid"  and 
the  "Disturbers"  being  equipped  in  this  manner.  In  this 


102  MOTOR  BOATS: 

case,  the  engines  must  be  driven  at  very  nearly  the  same 
speed  to  prevent  a  tendency  to  skidding  or  "yawing." 

Planes  in  Water. 

To  illustrate  the  principle  of  the  Hydroplane  clearly 
the  accompanying  sketches  1,  2,  3,  4,  5,  6,  7,  have  been 
prepared,  which  show  the  application  of  the  plane  in 
progressive  steps. 

In  Fig.  1  is  shown  the  plane  surface  AC  completely 
immersed  in  water  below  the  surface  or  water  line  WL. 
The  force  or  thrust  T  is  pushing  the  plane  from  right  to 
left  as  indicated  by  the  arrow  T.  As  the  plane  is  pushed 
forward,  the  water  in  front  of  the  surface  is  compressed 
with  a  pressure  F,  causing  the  water  to  rise  at  D  and  E 
and  to  pass  over  the  top  and  bottom  of  the  plane  at  A 
and  C.  Since  the  water  streams  cannot  close  up  instantly 
after  passing  the  plane  there  is  a  partially  open  and  vacu- 
ous space  left  at  G  which  is  more  or  less  occupied  by 
turbulent  spray  and  air  motions  indicated  by  the  whirling 
lines.  As  the  vacuum  acts  to  the  left  as  shown  by^  arrow 
G  it  opposes^  the  propelling  force  T,  causing  the  latter  to 
compensate  for  the  compression  F  plus  vacuum  G.  The 
top  and  bottom  streams  are  shown  reunited  at  R. 

The  plane  in  this  case  is  normal,  or  at  right  angles,  to 
the  direction  of  motion,  and  in  this  condition  will  balance 
when  T  is  applied  at  the  plane  center  B.  This  point  at 
which  the  forces  of  all  the  minute  stream  lines  are  sup- 
posed to  be  concentrated  is  known  as  the  "center  of  pres- 
sure" or,  in  other  words,  is  the  point  at  which  the  sum  of 
the  forces  acting  on  the  face  produce  no  tendency  to  turn 
the  plane  either  to  the  left  or  to  the  right.  (Position  of 
equilibrium.) 

A  second  condition  is  shown  by  Fig.  2  in  which  a  part 
of  the  plane  AC  is  above  the  water  level  WL,  an  ar- 
rangement that  considerably  changes  the  stream  lines. 
The  thrust  T  is  as  before  and  acts  in  the  same  direction, 


CONSTRUCTION  AND  OPERATION  103 

but  is  now  nearer  the  edge  C  as  the  pressure  on  the  plane 
is  now  only  between  D  and  C.  With  the  old  center 
of  pressure  at  the  center  of  the  plane  at  B,  the  new  center 
has  now  moved  down  by  the  distance  I  to  H.  It  is  evi- 
dent that  the  less  there  is  of  immersion,  the  lower  will  be 
the  center  of  pressure.  The  water  still  rises  in  front  of 
the  plane  as  at  ED  but  passes  at  the  ends  instead  of  the 
top  as  in  the  former  case.  The  vacuous  turbulent  space  G 
still  exists  but  is  no  longer  closed  by  the  stream  ED 
at  the  top.  This  open  space  allows  the  air  to  enter  at  N 
which  destroys  the  vacuous  drag  to  some  extent,  though 
not  all  together.  In  all  cases,  it  will  be  noted,  the  force  T 
has  been  principally  engaged  in  overcoming  the  impact 
of  the  water  in  front  and  the  effect  of  the  inertia  of  the 
water  at  the  rear.  The  inertia,  or  movement  of  the  water 
is  responsible  for  the  vacuum  established  at  G  since  this 
property  prevents  instant  closure  of  the  stream. 

In  Fig.  3  the  plane  AC  is  shown  inclined  to  the  direc- 
tion of  progress  by  the  angle  X.  Inclining  the  plane 
now  divides  the  water  forces  into  two  "components,  one 
being  a  vertical  force  L,  and  the  other,  the  old  thrust  T 
employed  in  overcoming  the  resistance.  As  we  now  have 
a  vertical  force  L,  acting  upwardly  and  against  gravi- 
tation, we  can  use  this  force  to  support  the  hull  instead 
of  a  buoyant  force.  This  is  the  elementary  principle  of 
the  hydroplane.  It  is  evident  from  examination  that  the 
smaller  we  make  the  angle  X  the  smaller  will  be  the 
propulsive  force  T  in  relation  to  the  lift  L,  although 
with  the  other  conditions  constant  we  will  have  a  smaller 
total  lift.  To  maintain  a  constant  lift,  say  equal  to  the 
weight  of  the  hull,  with  a  decreased  angle  we  must 
increase  the  speed  to  correspond  with  the  reduction  of 
X.  For  the  smallest  amount  of  thrust  T  to  support  a 
given  load  we  must  have  a  very  small  angle  X  and  a 
high  speed.  At  low  speeds  the  efficiency  of  the  drive 
is  decreased  on  account  of  the  large  angle  necessary  for 


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CONSTRUCTION  AND  OPERATION  105 

L  and  the  ensuing  low  ratio  between  L  and  T.  The 
point  B,  center  of  plane,  marks  the  old  center  of  pres- 
sure in  Fig.  1  with  the  normal  plane.  It  will  be  noted 
that  the  new  center  has  moved  back  by  the  distance  I. 

Unfortunately  the  center  of  pressure  varies  widely  and 
irregularly  with  a  change  in  the  angle  X  so  that  the 
center  of  pressure  at  different  angles  may  cause  the 
center  of  gravity  to  be  moved  to  L1  or  L2  according  to 
conditions.  For  stability  the  center  of  pressure  and  the 
center  of  gravity  should  be  coincident  to  prevent  the 
plane  from  assuming  a  new  angle.  Since  in  a  boat,  prac- 
tical conditions  make  the  shifting  of  the  load  impossible, 
the  location  of  the  gravity  center  is  usually  a  compromise 
between  extreme  conditions. 

Fig.  4  shows  the  application  of  the  principle  to  a 
"monoplane"  hull  (Single  plane)  in  which  AB  is  the 
bottom  planing  surface,  L  is  the  lift  numerically  equal  to 
the  weight  less  the  buoyancy,  and  M  is  the  wetted  sur- 
face. The  force  T  is  the  thrust  applied  at  CP,  the  cen- 
ter of  pressure,  and  at  the  intersection  of  L  and  T.  The 
arrows  show  the  stream  direction.  The  weight  of  the 
engine  E  plus  the  fuel  F,  plus  the  passengers  causes  the 
center  of  gravity  G  to  be  slightly  to  the  rear  of  the  lift 
line  L,  by  an  amount  I.  This  at  low  speed,  the  condition 
shown,  causes  the  hull  to  make  the  angle  X  with  the 
water  line  WL. 

In  Fig.  5  the  hydroplane  is  shown  at  full  speed,  the 
increased  lift  due  to  the  high  speed  lifting  the  greater 
part  of  the  hull  out  of  water.  The  length  of  wetted  sur- 
face M1  has  been  greatly  reduced  from  the  wetted  length 
M  in  Fig.  4  and  hence  the  resistance  and  frictional  power 
requirements  have  been  greatly  reduced.  The  angle  X1' 
has  been  reduced  owing  to  the  high  speed,  and  the  cen- 
ter of  gravity  now  lies  on. the  lift  line  L,  or  in  stable 
position  for  the  most  efficient  angle.  It  will  be  seen  that 
L  has  moved  back  to  G. 


106 


MOTOR  BOATS: 


Fig.  6  shows  one  of  the  early  pontoon  arrangements 
built  by  Henri  Fabre  which  is  composed  of  the  two 
floats  P1  and  P2,  connected  by  the  bar  R. 


F/G.7 

TWO  STEF>/-/YOS?O 

* 

In  Fig.  7  is  shown  a  "biplane"  or  "two-stepper"  which 
in  principle  is  similar  to  Fig.  6,  the  structural  difference 
being  that  the  two  planing  surfaces  are  combined  in  one 
hull.  This  type  is  very  extensively  used.  As  shown, 
the  hull  is  divided  into  two  separately  inclined  surfaces, 
P1  and  P2,  separated  by  the  step  S.  The  action  of  the 
water  is  clearly  shown  by  the  curved  lines  as  in  the  pre- 
vious examples,  the  lifts  due  to  the  two  planes  being 
shown  by  L1  and  L2,  and  the  total  lift  by  L.  As  shown 
by  the  dotted  area  at  the  rear  of  the  step,  there  is  a  con- 
siderable suction  which  produces  drag.  In  many  types 
an  air  tube  7  is  inserted  in  the  step  so  that  air  will  be 
admitted  to  break  the  suction. 


CHAPTER  XI 

CHOICE  OF  A  BOAT  MODEL. 

In  making  a  choice  of  a  boat  model,  whether  for  the 
purpose  of  amateur  boat-building  or  in  buying  a  com- 
pleted 'hull,  there  are  several  main  considerations  to  be 
taken  into  account.  First  of  these  is  the  question  of  sea- 
worthiness. If  the  boat  is  to  be  used  on  the  seacoast  or 
the  Great  Lakes,  the  possible  range  of  travel  and  the 
depth  of  the  waters  to  be  navigated  demand  a  greater 
beam  and  greater  stability  in  other  respects  than  are  re- 
quired in  craft  intended  for  the  navigation  of  narrow 
and  shallower  waters. 

The  problem  of  the  form  and  structure  of  the  boat  in- 
volves the  selection  of  a  craft  having  the  proper  carrying 
capacity,  stability  and  comfort,  designed  along  lines  that 
will  present  the  least  resistance  at  a  required  speed. 

If  the  inquirer  intends  to  build  his  own  boat  or  to  in- 
stall his  own  engine  in  the  hull  he  selects,  the  weight  of 
the  engine  to  be  installed  is  an  important  factor.  He 
will  do  well  to  obtain  the  views  of  an  experienced  boat- 
builder  or  of  a  marine  engineer,  capable  of  making  the 
necessary  calculations  of  the  displacement  of  a  boat. 

If  his  object  is  to  secure  a  boat  to  run  at  high  speed, 
he  will  need  a  model  in  which  the  lightest  possible  con- 
struction is  combined  with  the  strength  required  to  sup- 
port the  engine  and  resist  the  stresses  set  up  by  its 
vibration. 

If  he  desires  only  a  moderate  speed  boat,  he  may  select 
a  model  of  safer  and  stronger  construction,  of  greater 
beam  and  higher  freeboard,  having  the  advantages  of 
more  room  and  carrying  capacity ;  in  other  words,  a  craft 
of  a  more  seaworthy  and  general  safer  character. 


108  MOTOR  BOATS: 

The  infinite  variety  of  boat  models  now  offered  to  the 
public  in  all  stages  of  construction,  including  patterns, 
knock-down  frames  and  completed  hulls,  offers  a  wide 
range  of  choice.  Many  of  these  models  of  approved  con- 
struction, popular  among  boatmen  East  and  West,  are 
illustrated  in  these  pages.  On  every  body  of  water  other 
models  can  usually  be  seen  and  as  a  rule  the  person  who 
starts  out  to  purchase  a  boat  or  to  construct  a  hull  for 
himself  has  a  fair  general  idea  of  the  kind  of  craft  he 
requires.  . 


18'  and  23'  Dories. 
(Pioneer  Boat  &  Pattern  Co.,  Bay  City,  Mich.) 

A  number  of  the  boats  illustrated  in  this  work  have 
come,  by  reason  of  long  and  successful  operation,  to  be 
regarded  almost  as  standard  models  and  the  novice  in 
motor  boating  will  not  go  far  wrong  if  he  selects  one  oi 
these  boats  of  generally  approved  design. 

As  stated  elsewhere,  the  novice  should  be  careful  to 
avoid  "freaks,"  that  is  models  in  which  some  peculiar 
individual  idea  or  ideas  have  been  embodied  at  the  ex- 
pense of  recognized  lines  of  construction.  Freaks  are  apt 
to  prove  expensive,  even  as  experiments,  and  the  wise 
boatman  usually  sticks  to  approved  designs,  leaving  it 
to  skilled  naval  architects  to  originate  new  ideas  in  design 
and  have  them  thoroughly  tested  before  recommending 
them  for  general  adoption. 

The  matter  of  the  proportion  of  the  length  of  the  boat 
to  its  beam  is  one  upon  which  no  definite  rule  can  be 


CONSTRUCTION  AND  OPERATION  109 

laid  down.  The  higher  the  speed  required,  the  narrower 
the  proportional  beam  as  a  rule.  The  limit  in  present 
practice  is  the  ration  of  9  or  10  to  1  for  high  speed  boats 
and  the  ratio  ranges  down  to  4,  4^,  or  5  to  1,  which  is  the 
proportion  of  the  length  to  beam  in  small  and  low  speed 
boats.  Moderate  sized  craft  designed  for  fair  speed,  sea- 
worthiness and  comfort  may  show  a  ratio  of  5^,  6,  or  7 
to  1  between  length  and  beam. 

The  following  table  shows  the  length  and  beam,  engine 
horse  power,  etc.,  in  a  typical  series  of  boat  models  built 
on  the  New  England  coast : 

Length             Beam                       H.  P.  Number  of 

Cylinders 

iy2to    2  1 

2y2  to    3  1 

3^  1 

4  1 

5  1 

6  2 

6  2 

7  2 

8  2 
8  2 

32ft.  7ft.    3  in.  10  2 

35ft.  7ft.  10  in.  10      to  13  2 

Careful  sailors  agree  that,  speaking  generally,  a  launch 
should  have  a  beam  about  one-fifth  of  her  length  on  the 
water  line,  when  it  is  intended  for  seagoing  or  to  with- 
stand heavy  weather.  In  small  boats  the  beam  should 
be  about  one-fourth  of  the  length  on  the  water  line.  This 
applies  only  to  boats  of  moderate  to  fair  speed. 

The  draft  of  a  boat  is  determined  by  the  form  of  the 
hull  and  weight  of  the  loaded  structure.  Increase  of  the 
beam  results  in  lessening  the  draft,  and  vice  versa.  As  a 
rule,  except  for  very  shallow  waters,  the  question  of 


16ft. 

4ft. 

6  in. 

18ft. 

4ft. 

Sin. 

20ft. 

5ft. 

6  in. 

22ft. 

5ft. 

Sin. 

25ft. 

6ft.. 

3  in. 

25ft. 

6ft. 

6  in. 

28ft. 

6ft. 

6  in. 

28ft. 

6ft. 

Sin. 

30ft. 

6ft. 

10  in. 

32ft. 

7ft. 

110 


MOTOR  BOATS: 


draft  need  not  deeply  concern  the  purchaser  of  a  boat. 
It  will  take  care  of  itself,  provided  the  length  and  beam 
are  suitably  proportioned  and  the  lines  of  the  boat  are 
of  approved  design. 

General  Form  of  the  Hull. 

As  regards  the  general  form  of  the  hull,  there  are  cer 
tain  principles  that  may  be  mentioned  here;  as,  for  in- 
stance, the  flare  at  the  bow  and  sides  from  the  water  line 


Types  of  Stems  and  Sterns. 
(Bath  Marine  Construction  Co.,  Bath,  Me.) 


CONSTRUCTION  AND  OPERATION 


111 


to  the  sheer.  The  greater  the  flare  outward,  as  a  rule,  the 
less  water  the  boat  will  ship  in  a  seaway,  but  flare  re- 
tards speed,  while  adding  to  comfort  and  safety.  This  is 
seen  in  the  seagoing  dory  with  its  splendid  stability  in  all 
weathers. 

For  seagoing  craft  a  wedge-shaped  bottom  is  preferable 
and  in  heavy  weather  adds  greatly  to  the  comfort  of  the 
occupants. 


21  'x4'  6"  Runabout. 
(Bath  Marine  Construction  Co.,  Bath,  Me.) 

A  certain  amount  of  sheer  or  rise  at  bow  and  stern  is 
another  desideratum  in  seagoing  craft  and  this  applies  to 
boats  intended  for  use  on  the  Great  Lakes,  where  heavy 
weather  is  apt  to  be  encountered  and  conditions  often 
strongly  resemble  those  encountered  on  the  seacoast. 


112  .  MOTOR   BOATS: 

The  sheer  is  always  greater  at  the  bow  than  at  the  stern 
and  adds  to  the  lifting  power  of  the  hull  in  a  seaway. 

A  certain  amount  of  decking  should  be  fitted  in  all 
open  launches  at  the  bow  and  stern.  The  forward  deck 
helps  to  keep  the  boat  dry  and  the  decking  aft  protects 
the  occupants  in  heavy  weather  from  "following"  waves 
climbing  over  the  stern.  Such  decks  do  not  decrease  the 
capacity  of  the  boat  since  the  space  beneath  can  be  used 
for  stowage,  and  they  add  greatly  to  comfort  and  safety, 
by  keeping  the  machinery,  accessories,  clothing,  etc.,  dry. 
A  certain  width  of  deck  should  be  fitted  the  whole  length 
of  the  boat  on  either  side  and  these  side  decks  should  not 
be  made  too  narrow. 

The  height  of  the  coaming  or  washboard  around  the 
cockpit  is  a  matter  of  choice  and  is  governed  by  consider- 
ations of  appearance  and  convenience.  A  high  coaming 
helps  to  keep  out  spray. 

Cruising  Craft. 

Cruisers  are  distinguished  mostly  by  the  character  of 
the  cabin  fittings.  Some  have  a  short  cabin  with  a  large 
cockpit,  while  in  others  most  of  the  interior  space  is  oc- 
cupied by  the  cabin,  with  a  small  cockpit  aft. 

Cabins  are  often  of  what  is  called  the  trunk  type,  a 
gangway  to  the  bow  being  left  on  either  side  of  the  trunk. 
Another  type  of  cruiser  has  a  flush  deck  forming  the 
cabin  top,  in  which  case  the  sides  of  the  boat  are  brought 
up  flush  and  the  deck  may  be  slightly  rounded  to  form 
a  "turtle  back."  This  style  of  cabin  affords  more  room 
inside  and  by  many  is  regarded  as  less  liable  to  leakage 
in  a  heavy  sea. 

Naval  architects  have  rung  the  changes  on  these  two 
leading  types  of  cruisers,  so  that  a  wide  range  of  choice 
is  offered  to  the  amateur  builder  or  purchaser,  and  cabin 
cruisers  nowadays  may  be  a  delight  to  the  eye  by  their 
handsome  appearance  while  at  the  same  time  affording  a 
maximum  of  accommodation  for  comfortable  cruising. 


CONSTRUCTION  AXD  OPERATION  113 

Finished  Boats. 

The  large  boatbuilders  endeavor  to  maintain  a  stock 
of  completed  boats  ready  for  immediate  shipment,  but 
as  the  majority  of  purchasers  prefer  an  interior  arrange- 
ment and  finish  to  meet  their  own  tastes,  their  principal 
stock  is  often  of  bare  hulls,  which  can  be  completed -on 
short  notice,  thus  giving  to  each  purchaser  a  boat  built 
to  his  special  order  but  at  regular  prices  and  without  de- 
lay. Each  purchaser  is  often  given  the  option  of  various 
interior  arrangements,  or  such  special  arrangement  as  he 
may  specify.  Or,  if  special  size,  design,  or  construction 
is  desired,  they  will  build  to  your  special  order  upon  re- 
ceipt of  plans  and  specifications,  or  will  submit  plans  for 
approval  if  you  give  them  an  idea  of  what  you  wish,  and 
quote  you  special  prices  for  such  construction. 

Boatbuilders'  Terms. 

The  following  are  typical  boatbuilders'  terms : 

"Twenty-five  per  cent  with  order  and  balance  when 
notified  that  goods  are  ready  to  ship,  or  by  sight  draft 
attached  to  bill  of  lading,  as  directed.  Full  amount  with 
order  will  generally  facilitate  shipment. 

"On  patterns :  Cash  with  order,  or  builders  will  ship 
by  express  C.  O.  D.  subject  to  examination  and  approval. 
All  patterns  guaranteed  to  be  perfectly  accurate  in  every 
phase  and  particular.  If  you  find  that  they  are  not ;  in 
fact,  if  you  are  not  thoroughly  elated  with  them  after 
you  have  tried  them,  notify  the  makers  and  they  will  re- 
turn your  money  cheerfully/' 

Specifications  For  Wooden  Launch  Hulls. 

The  following  are  up-to-date  specifications  for  wooden 
launch  hulls,  covering  the  regular  form  of  construction 
of  a  leading  New  York  engine  and  boatbuilding  concern, 
the  Gas  Engine  £  Power  Co.  and  Charles  L.  Seabury 
&  Co.,  Consolidated,  of  Morris  Heights  on  the  Harlem. 

These  specifications  may  be  regarded  as  typical  of  the 
best — which  is  often  the  cheapest — construction. 


114  MOTOR  BOATS: 

Timber — All  timber  thoroughly  seasoned  and  free  from 
large,  loose  and  rotten  knots,  sap  and  shakes,  or  other 
imperfections  of  growth  detrimental  to  satisfactory 
service. 

Keel — Best  oak,  in  one  piece  where  practicable,  and 
where  splicing  is  necessary  on  account  of  length,  the 
scarfs  long  and  locked,  and  through  fastened  with  cop- 
per bolts,  riveted. 

Sternpost — Of  oak  let  into  keel,  secured  by  brass  dove- 
tail plates  on  each  side,  fastened  with  copper  rivets,  and 
the  counter  dovetailed  into  the  sternpost.  Stop-waters 
put  in  all  joints  below  the  water  line. 

Frames — Of  oak  or  elm,  spaced  10  inches  center  to 
center,  straight  grain,  steam  bent,  in  one  length  from 
the  keel  to  gunwale,  fastened  to  deadwoods  with  composi- 
tion nails  and  brass  screws.. 

Floor  Timbers — Of  elm  or  oak,  running  well  up  the  side 
of  each  frame  and  fastened  with  copper  rivets  and  galvan- 
ized iron  boat  nails.  Limbers  cut  in  frames  between  the 
water-tight  bulkheads. 

Keel  Battens — Of  quartered  oak,  fastened  with  brass 
screws  and  with  copper  rivets"  through  planking. 

Risings — Of  oak,  spruce  or  elm,  fastened  with  galvan- 
ized wrought-iron  boat  nails. 

Clamps  and  Stringers — Of  yellow  pine  in  long  lengths, 
through  fastened  where  practicable  with  copper  rivets. 

Planking — Selected  white  cedar,  or  cypress,  in  long, 
narrow  strakes,  fastened  on  each  edge  at  each  frame  with 
copper  nails;  all  fastenings  bored  for  (not  driven),  riveted 
on  copper  burrs;  all  nail  and  screw  holes  countersunk 
for  wood  plugs  set  in  white  lead.  Butts  of  planking  com- 
ing together  between  frames,  fastened  to  quartered  oak 
butt  blocks,  fitted  from  frame  to  frame  and  through 
fastened,  with  at  least  ten  rivets  in  each  butt  block,  same 
style  as  the  plank  fastenings.  The  forward  and  after  ends 


CONSTRUCTION  AND  OPERATION  115 

fastened  with  brass  screws.  All  planks  to  be  planed  on 
the  inside  and  made  to  fit  snugly  on  the  frames.  The 
outside  planking  planed  perfectly  fair,  smooth  and  even, 
thoroughly  sandpapered  before  painting.  The  seams  of 
planking  caulked  with  cotton,  payed  writh  white  lead  paint 


28'  8-10  H.  P.  Hunting  Cabin  Launch — Gas  Engine  &  Power  Co. 
and  Charles  L.  Seabury  &  Co.     (Consolidated.) 

and  filled  with  marine  putty;  all  through  fastenings  of 
copper  clinched  over  copper  burrs.  All  joints  well  painted 
before  being  put  together. 

Water-Tight  Bulkheads — Of  clear  wrhite  pine,  cedar  or 
cypress,  writh  flush  lap  seams,  the  laps  and  ends  fastened 
with  copper  rivets  and  brass  screws.  Seams  caulked 
with  cotton  and  payed  with  white  lead  paint.  Stop 
waters  put  in  seams  of  planking  at  the  bulkheads  to  in- 
sure water  tightness.  All  bulkheads  finished  with  tongued 
and  grooved  chamfered  edge  hardwood  ceiling. 

Upperstrake — Of  quartered  oak,  fastened  the  same^  as 
the  planking. 

Planksheer,  Coaming  and  Guard  Moldings — Of  quar- 
tered oak,  fastened  closely  with  brass  screws.  The  coam- 


116  MOTOR  BOATS: 

ing  fitted  with  two  bronze  oarlocks  and  sockets,  and  the 
planksheer  with  bronze  fender  cleats. 

Decks — Of  quartered  oak  in  narrow  strakes,  caulked 
with  cotton,  payed  with  paint,  and  filled  with  marine 
putty.  Hatch  with  brass  lifts  fitted  over  the  tiller,  and 
over  the  trap  screw  on  gasolene  tank.  A  six-inch  diameter 
bronze  deck  ring  fitted  over  a  wrought-iron  galvanized 
hawser  ring,  which  is  fastened  to  the  inside  of  the  stem 
with  two  galvanized  iron  screw  bolts. 

When  a  sternpost  projects  above  the  planking,  a 
wrought-iron  galvanized  ring  bolt  will  be  fastened 
through  same,  for  lifting  the  boat  and  making  fast  the 
hawsers. 

Deck  Beams  and  Framing — Of  oak ;  the  deck  over  gaso- 
lene tank  constructed  in  such  a  manner  that  it  can  be  re- 
moved in  one  piece,  so  that  the  tank  may  be  readily  in- 
spected if  so  desired. 

Seat- Ledges  and  Framing — Of  quartered  oak,  fastened 
with  brass  screws. 

Seat  and  Interior  Trim — Of  white  ash,  fastened  with 
brass  screws.  Lockers  where  specified  will  have  lids 
on  top  of  seats  fitted  with  brass  butts  and  lifts.  Inside 
of  the  lockers  sheathed  with  soft  wood,  tongued  and 
grooved  ceiling,  and  the  fronts  with  white  ash  tongued 
and  grooved  ceiling,  secured  at  the  floor  with  quarter- 
round  moldings,  and  with  facia  on  top. 

Floor  Beams — Of  oak  on  each  frame,  with  stanchions 
where  required. 

Flooring — Of  white  pine  tongued  and  grooved,  in  nar- 
row strakes,  with  hatches  in  the  center  well  battened 
and  secured  with  bronze  flush  floor  buttons. 

The  frames  and  clamps  above  seats  finished  with  white 
ash  or  oak. 

All  fastenings  in  the  joiner  work  countersunk,  and  the 
heads  covered  with  wood  plugs  set  in  with  marine  glue. 


CONSTRUCTION  AND  OPERATION  117 

Painting  and  Varnishing — Inside  of  the  hull  to  have 
two  coats  heavy  lead  paint.  Outside  of  planking  to  be 
given,  first,  a  priming  coat  of  lead,  and  afterward  two 
more  coats  of  white  lead  paint  above  water  line,  and  two 
coats  of  the  best  anti-fouling  composition  paint  in  red  or 
green  color  on  under  body.  Floor  and  inside  of  lockers 
is  given  two  coats  best  lead  color  paints.  Decks,  coaming, 
guard  moldings  and  interior  trim  are  finished  with  three 
coats  of  best  spar  varnish. 

Miscellaneous — Cotton-covered  wire  core  steering  line. 
Brass  rudder  and  post.  Brass  skeg  fastened  with  brass 
wood  screws.  Brass  quadrant  keyed  on  post  and  fastened 
with  brass  set  screws.  Brass  rudder  post  guide  with 
stuffing-box  inside,  fastened  with  brass  or  Tobin  screw 
bolts  set  up  with  nuts  on  washers,  or  a  heavy  brass  pipe 
screwed  into  the  wrood  with  a  large  stuffing-box  on  the 
upper  end. 

One  pair  ash  oars  fastened  in  cockpit  with  leather 
straps,  with  buckles. 

Square  sterns  rabbeted  to  receive  the  end  of  planking, 
reinforced  on  the  inside  with  a  heavy  hackmatack  knee 
fastened  with  copper  rivets  clinched  over  copper  burrs. 

Rudders  for  square  sterns  of  oak,  with  bronze  braces, 
gudgeons,  cap  and  tiller ;  the  tiller  fastened  to  cap  with 
brass  screw  bolts,  arranged  so  that  the  rudder  may  be 
readily  unshipped. 

Transom  knees  of  oak,  hackmatack,  or  chestnut, 
fastened  to  transom  and  through  clamps  and  upper  strake 
with  copper  rivets,  clinched  over  copper  burrs. 

Steering  gear  pulleys  of  heavy  bronze  fastened  with 
bronze  or  brass  screw  bolts  where  practicable,  otherwise 
with  brass  wood  screws. 

Stem  band  of  half-round  brass,  drilled  and  countersunk, 
well  fastened  with  brass  wood  screws,  all  finished  smooth 
and  fair.  The  upper  end  to  extend  and  fasten  to  the 
planksheer.  and  to  run  well  under  the  keel. 


118  MOTOR  BOATS: 

Motor  compartment  of  yacht  tenders  lined  with  sheet 
brass  from  keel  to  about  12  inches  above  floor. 

Gasolene  tank  made  of  heavy  copper,  with  both  riveted 
and  soldered  seams,  reinforced  inside  with  galvanized 
sheet-iron  stiffening  plates,  riveted  and  soldered,  arranged 
with  safety  valve  and  trap  screw  on  top,  and  tank  placed 
in  copper  pan  with  drip  pipe  leading  overboard,  and  a 
vent  pipe  to  the  outside  of  hull,  all  rigidly  secured  in 
compartment  separated  from  body  of  hull  by  water-tight 
bulkhead.  Wherever  practicable,  the  feed  pipe  from  tank 
to  motor  is  carried  on  outside  of  the  hull,  to  insure  ad- 
ditional safety  by  water  insulation. 

The  above  specifications  are  for  boats  and  launches  for 
use  in  salt  water,  hence  galvanized  and  copper  hardware 
is  specified  throughout. 

Typical  Western  Construction. 

Typical  construction  on  the  Great  Lakes  is  exemplified 
in  the  motor-boats  built  by  the  DeFoe  Boat  and  Motor 
Works,  of  Bay  City,  Michigan.  As  there  are  special  fea- 
tures found  in  the  DeFoe  boats  not  found  in  any  other, 
we  give  the  following  detailed  description  of  their  con- 
struction : 

"The  entire  frame  is  of  perfect,  straight-grained  white 
oak.  Ribs  are  steam  bent  and  closely  spaced,  from  4  to 
8  inches  apart,  depending  on  the  size  of  boat  and  thick- 
ness of  planking.  The  sheerstrake  is  of  either  oak  or  ma- 
hoganized  birch  to  correspond  with  the  decks  and  coam- 
ing, and  balance  of  planking  of  clear  Louisiana  red  cy- 
press, with  all  fastenings  either  screwed,  bolted  or  clinch 
nailed,  making  the  strongest  possible  construction. 

"All  joints  are  reinforced  between  frames  with  oak  butt 
blocks.  The  plank  seams  are  caulked  with  cotton,  payed 
with  white  lead  and  puttied  flush,  nail  heads  countersunk 
and  puttied  and  screw  and  bolt  heads  plugged,  leaving  a 
perfectly  smooth  surface. 


CONSTRUCTION  AND   OPERATION  119 

"Inside,  beneath  the  covering  boards,  heavy  oak  clamps 
are  bolted  to  the  sheerstrake  and  ribs,  adding  strength 
and  firmness  to  the  whole  frame.  Deck  beams  and  breast 
hooks  are  sawed  to  shape  and  firmly  fastened  in  position. 
Covering  boards  cut  to  shape.  Decking  laid  in  narrow 
stuff,  caulked,  payed  and  puttied  flush — the  only  way  to 
make  a  perfect  deck. 


DeFoe  Fantail  Stern  Launch. 

"Bulkheads  at  each  end  of  the  cockpit  are  paneled  with 
doors,  giving  easy  access  under  the  decks.  The  gasolene 
tank  is  so  arranged  that  it  can  be  easily  removed  at  any 
time,  and  is  of  extra  heavy  galvanized  iron  with  swash 
plates  fore  and  aft  and  athwartship  to  prevent  undue 
strain  by  the  shifting  of  the  gasolene  in  a  seaway.  The 
floor  is  covered  with  linoleum  and  entire  cockpit  is 
artistically  paneled  throughout. 

"Rudder  is  of  steel  plate.  Steering  boards  clear,  but 
with  all  parts  of  the  steering  gear  easily  accessible  at  any 
time  for  repairs.  Steering  wheel  of  polished  brass  with 
mahogany  grips  and  drum.  Cleats,  chocks  and  all  other 
deck  and  interior  hardware  of  polished  brass." 

A  Special  Michigan  Steel  Boat. 

A  fine  example  of  a  steel  motor-boat  in  popular  de- 
mand is  the  1910  Special  18-foot  model  built  by  the  Mich- 
igan Steel  Boat  Company,  of  which  two  photographic 
illustrations  are  shown.  This  boat  has  a  beam  of  4  feet  6 
inches  and  the  cockpit  is  11  feet  4  inches  long.  The 
depth  is  2  feet  amidships,  2  feet  7  inches  forward,  and  1 
foot  10  inches  aft.  Equipped  with  a  3^2  H.  P.  Detroit 


120 


MOTOR  BOATS: 


18'  Special  1910  Auto  Boat,  With  3J4  H.  P.  Detroit  Engine. 
(Michigan  Steel  Boat  Co.,  Detroit,  Mich.) 


CONSTRUCTION  AND  OPERATION  121 

engine,  the  boat  makes  a  speed  of  10  miles  an  hour.  It 
seats  ten  persons  in  all,  the  forward  cockpit  seating  six, 
having  seats  4  feet  6  inches  long  and  10  inches  wide.  The 
net  weight  of  the  boat  is  650  pounds ;  crated  for  domestic 
shipment,  850  pounds.  The  measurements  boxed  are  18 
feet  3  inches  by  4  feet  8  inches  by  3  feet  4  inches,  or  284 
cubic  feet.  The  price  of  this  model  complete  with  en- 
gine installed  ($147,  crated,  f.  o.  b.  cars  at  Detroit)  brings 
it  within  the  reach  of  the  most  moderate  incomes.  In 
materials,  workmanship  and  power,  this  1910  boat  is  fully 
up  to  the  well-known  standard  of  the  Michigan  Steel 
Boat  Company  in  every  respect. 

The  launch  can  be  equipped  writh  an  engine  as  large 
as  12-14  H.  P.  if  desired.  With  such  an  engine  installed 
it  has  made  actual  speed  over  a  measured  course  of  19 
miles  an  hour.  Of  course  the  price  with  the  larger  engine 
is  comparatively  higher. 

"Matthews"  Craft. 

Among  the  boat-builders  who  have  aided  greatly  in 
the  recent  development  of  motor-boating  by  the  produc- 


tion of  excellent  and  popular  models  is  The  Matthews 
Boat  Company,  of  Port  Clinton,  Ohio.     The  methods  of 


122 


MOTOR  BOATS: 


rt 


Usual  Method. 


Matthews'  Method  of  Construction. 


CONSTRUCTION  AND  OPERATION  123 

construction  adopted  by  this  concern  possess  many 
features  of  general  interest. 

For  example,  as  shown  in  the  illustration,  the  method  of 
construction  followed  by  some  builders-  includes  a  small 
single  keel;  two-piece  frames  on  top  of  keel,  cut  at  the 
weakest  point ;  large  bevel  seams  in  planking,  stuffed  with 
calking;  open  seam  at  garboard,  to  cause  "garboard  leak- 
age," and  garboard  plank  fastened  to  frames  only.  The 
Matthews  method  includes  stronger  "backbone"  con- 
struction; garboard  plank  lapped  under  keel,  to  obviate 
open  seam  and  give  longitudinal  fastenings;  single-piece 
frames,  rabbeted  or  slotted  under  inner  keel  to  increase 
strength  wrhere  most  needed,  and  small,  tight  seams  of 
planking,  with  small  strand  of  calking. 

The  Matthews  open  launches  have  been  built  in  large 
numbers  and  have  attained  popularity  as  moderate-priced 
outfits.  Their  cabin  cruisers  are  also  well-known  craft. 

These  boats  are  mentioned  only  as  illustrations  of  the 
wide  range  of  choice  offered  nowadays  to  the  man  who 
would  a-boating  go.  No  matter  whether  his  main  de- 
sideratum is  speed,  safety  or  luxury — or  a  combination  of 
all  these  points — the  boat  builders  stand  ready  to  supply 
his  needs  at  short  notice. 


124 


MOTOR  BOATS: 


mm 

mlm* 
sslsm 


CHAPTER  XII 

PRACTICAL  BOATBUILDING. 
1.     Boat  Patterns  and  Knock-Down  Frames. 

The  amateur  boatbuilder  of  the  present  day  enjoys  im- 
mense advantages  over  his  predecessor  of  the  past.  He 
need  no  longer  work  by  rule  of  thumb  or  rely  on  his  own 
ingenuity  in  the  important  matters  of  design  and  work- 
ing plans.  For  a  few  dollars  he  can  buy  all  the  necessary 
boat  patterns,  selecting  his  design  from  among  hundreds 
offered  for  his  choice  by  the  boatbuilders  who  make  a 
specialty  of  this  feature  of  the  business.  In  obtaining 
such  patterns,  care  should  be  taken  of  course  to  order 
them  of  recognized  experts  in  boatbuilding  whose  pat- 
terns may  be  depended  upon  to  be  those  of  tried  and  ap- 
proved models.  This  is  particularly  important  when  the 
amateur  contemplates  building  a  seagoing  craft  or  one 
for  the  navigation  of  the  Great  Lakes  and  deep  waters 
generally.  In  the  construction  of  water  craft  it  is  always 
best  to  err  on  the  side  of  safety.  In  ninety-nine  cases  out 
of  a  hundred,  there  is  more  pleasure  for  your  friends  in 
a  roomy  and  thoroughly  seaworthy  craft  than  in  a  boat 
built  according  to  plans  that  sacrifice  every  considera- 
tion of  comfort  to  speed,  or  that  have  not  been  thor- 
oughly tested  and  tried  out  in  actual  models. 

For  this  reason  it  will  be  best  for  the  amateur  to  rely 
to  a  considerable  extent  upon  the  judgment  of  the  skilled 
marine  designers  and  builders  who  have  made  modern 
boatbuilding  almost  an  exact  science.  If  he  is  not  al- 
ready in  touch  with  such  firms  a  communication  ad- 
dressed to  any  of  the  hull  builders  or  marine  engine 


126 


MOTOR  BOATS: 


manufacturers  named  in  this  work  will  put  him  directly 
in  the  way  of  all  desired  information. 

We  do  not  wish  to  be  understood  as  discouraging  ama- 
teur designing.  On  the  contrary,  some  very  successful 
models  have  resulted  from  the  work  of  amateurs,  but 
amateurs  should  have  especial  regard  to  the  matters  of 
safety  and  staunchness. 

All  boatmen  have  their  preferences — and  their  dislikes 
— as  to  types  and  designs  of  boats  for  any  particular  pur- 
pose. The  development  of  motor-boating  has  stimulated 
and,  in  fact,  has  awaked  the  inventive  or  designing  abili- 
ties of  many  a  man,  so  that  today  successful  models  of 
power  boats  are  innumerable.  The  illustrations  shown 
in  this  work  are  of  a  necessarily  limited  number  of  the 
most  popular  designs.  With  the  large  number  of  boat- 
building concerns  now  making  stock  models,  the  yacht  de- 
signers, and  last,  but  not  least,  the  amateur  designer,  the 
most  critical  boatman  can  find  a  style  of  boat  which, 
with  slight  changes,  suits  his  particular  fancy. 


Pioneer  "Perfect"  Frames,  Set  Up  and  Knocked  Down. 
(Pioneer  Boat  &  Pattern  Co.,  Bay  City,  Mich.) 

The  amateur  builder  who  wishes  to  pursue  only  a  half 
way  course  in  construction  and  to  avoid  the  heavier 
work  of  frame  building  can  avail  himself  of  the  knock- 
down frame  method.  There  are  reliable  boat-building 


CONSTRUCTION  AND  OPERATION  127 

firms  which  supply  motor-boat  frames  that  can  be  as- 
sembled without  boring  a  hole  or  cutting  a  shaving.  In 
fact,  the  builders  furnish  boats  in  any  stage  of  construc- 
tion from  patterns  to  completed  craft,  ready  to  put  in  the 
water  and  run.  Thus,  the  amateur  can  put  in  any  amount 
of  individual  construction  work  that  he  may  desire.  He 
can  build  his  boat  entirely  by  himself;  he  can  assemble 
the  frames,  in  whole  or  in  part,  and  put  on  the  finishing 
touches  according  to  his  own  ideas  or  the  plans  of  a  naval 
architect ;  he  can  buy  a  bare  hull  or  a  completed  hull,  of 
wood  or  steel,  and  install  his  own  engine ;  or  he  can  pur- 
chase a  boat  already  powered  with  a  suitable  engine  and 
ready  for  the  water. 

Why  Build  Your  Own  Boat? 

The  question  is  often  asked,  is  it  cheaper  to  build 
one's  own  boat?  Glance  at  any  boat-builder's  price  list. 
Suppose  you  want  a  25-foot  launch.  Patterns  will  cost 
you,  say,  $6.00;  hardware  of  iron,  $5.00;  planking  and 
decking,  about  $20.00;  oak  for  frame,  about  $8.00.  Say 
$45.00  to  $50.00  to  cover  everything  except  your  time,  and 
this  you  take  at  odd  hours,  and  the  result  is  a  boat  that 
the  builders  sell  at  $325.00  and  cannot  afford  to  sell 
cheaper.  In  most  cases  you  build  your  own  boat  at  from 
one-quarter  to  one-fifth  the  money  cost  of  a  completed 
boat. 

Can  a  man  who  is  not  a  mechanic  use  boat  patterns 
and  build  a  boat?  Any  man  or  boy  who  can  read  the  in- 
struction sheets  and  is  capable  of  sawing  a  board  off  or 
driving  a  nail,  can  build  a  boat  by  the  pattern  .system, 
and  an  extra  good  one  at  that. 

\Yhat  advantages  are  there  in  building  one's  own  boat? 
First,  the  advantage  in  cost  stated  above.  Second,  the 
satisfaction  anyone  feels  in  being  able  to  construct  some- 
thing, particularly  if  it  is  that  something  which  has  al- 
ways aroused  the  keenest  instincts  of  man's  nature  to 


128  MOTOR  BOATS: 

overcome  the  elements,  namely,  a  boat.  Then  one's  en- 
joyment in  sailing  a  boat  of  his  own  construction  is  dou- 
ble what  it  would  be  were  he  to  buy  a  boat  of  another's 
make.  That  is  human  nature. 

The  modern  boat  patterns  are  in  every  feature  an  im- 
provement on  those  heretofore  offered.  The  best  build- 
ers offer  nothing  freakish,  nothing  untried,  nothing  that 
they  wish  to  sell  simply  because  it  is  new,  but  a  pattern 
system  that  is  the  very  best  that  experience  and  expert 
design  and  construction  can  produce.  They  believe  in 
common  sense  and  the  steady  and  solid  progress  which 
comes  from  building  on  a  solid  foundation  of  known  facts. 

The  amateur  builder  should  scrupulously  avoid  freaks. 
This  is  a  well  known  term  in  the  boating  world  and  is  ap- 
plied to  the  craft  that  is  built  around  a  single  good  fea- 
ture to  the  exclusion  of  all  others,  to  satisfy  a  passing 
popular  fad. 

The  Boat  Pattern  System. 

Bay  City,  Michigan,  is  conceded  to  have  been  the  birth- 
place of  the  pattern  system  and  there  it  has  been  devel- 
oped from  a  mere  experiment  into  a  business  of  gigantic 
proportions — and  this,  it  is  claimed,  by  the  inherent 
merits  of  the  boat  pattern  idea.  The  system  is  now  a 
demonstrated  success  and  large  boat-building  concerns 
in  the  eastern  states,  as  well  as  the  pioneers  of  the  Middle 
West,  now  furnish  excellent  boat  patterns  for  the  use  of 
amateur  builders. 

During  the  period  of  development  some  of  the  defects 
in  boat  pattern  systems  have  been  due  to  the  patterns 
themselves,  but  more  often  to  the  fact  that  boats  from 
which  they  were  taken  were  not  designed  with  a  view 
of  securing  patterns  of  the  greatest  simplicity  and  which 
would  present  the  least  difficulties  to  the  amateur  in  the 
reproduction  of  the  craft. 


CONSTRUCTION  AND  OPERATION 


129 


After  years  of  careful  study  and  experiment  the  leaders 
in  the  industry  have  incorporated  into  their  methods, 
both  as  to  patterns  and  knock-down%  frames  and  boats, 
those  features  which  have  commended  themselves  to  the 
trade  and  have  demonstrated  their  practicability  and  ex- 
cellence after  years  of  trial,  and  have  added  thereto  such 
new  ideas  as  they  have  gained  by  years  of  experience, 
observation  and  experiment.  Their  patterns  are  not  taken 
from  models  built  promiscuously  for  a  number  of  years, 
but  every  set  of  patterns  is  taken  from  a  boat  constructed 
for  the  purpose  of  obtaining  the  simplest  and  most  per- 
fect patterns  involving  the  least  possible  difficulties  for 


^^^•IP*^ 

x. 


Built  From  DeFoe  Patterns. 

the  amateur  in  their  use,  in  the  construction  of  a  boat 
which,  when  completed,  will  embody  the  latest  and  most 
approved  ideas  of  design  and  construction. 

The  DeFoe  Boat  and  Motor  Works  of  Bay  City,  Mich., 
well  known  among  the  boatbuilders  of  the  Great 
Lakes,  explaining  the  boat  pattern  system,  say :  "We 
have  endeavored  to  make  our  pattern  system  a  sys-tem 
in  fact,  not  only  as  to  the  construction  and  use  of  the 


130  MOTOR  BOATS: 

patterns,  but  in  the  design  and  method  of  construction  of 
the  boats  from  which  they  are  taken.  While  there  is  no 
real  reason  under  our  system  why  he  cannot  build  a  large 
boat  as  easily  as  a  small  one,  yet  the  amateur  builder,  as 
a  rule,  first  undertakes  the  construction  of  a  small  boat 
and  then  almost  invariably  builds. a  larger  one  the  next 
season.  But  if  every  size  and  style  of  boat  is  constructed 
on  wholly  different  principles  and  by  different  methods, 
the  experience  gained  in  the  construction  of  the  first  boat 
will  be  of  little  assistance  in  building  the  second.  Under 
our  modern  system,  however,  every  boat  we  build,  either 


DeFoe  Speed  Launch  No.  630. 

large  or  small,  and  regardless  of  the  style,  is  built  upon 
the  same  general  plan  or  system.  Thus  the  stern,  keel, 
pipelog,  and  other  portions  of  the  frame  are  always  made 
and  put  together  in  the  same  way,  and  the  same  general 
method  is  followed  in  planking,  etc. 

"This  is  a  vast  improvement,  and  one  which  puts  the 
modern  system  a  good  long  stride  in  advance.  For  when 
the  amateur  has  built  his  first  boat  by  this  system  he  can 
build  a  second,  regardless  of  size  or  design,  with  scarcely 
a  reference  to  the  instruction  sheets  and  illustrations, 
making  a  great  saving  in  time  and  expense,  as  he  will 
know  from  his  first  experience  the  position  and  fastening 
of  every  part  of  the  frame,  the  manner  in  which  it  is  set 
up,  and  the  method  of  planking  and  completing  the  hull. 

"Many  of  our  customers,  we  find,  get  their  boats  free  in 
a  novel  manner.  They  first  build  a  boat  and  sell  it  and 
with  the  proceeds  purchase  patterns  and  possibly  a  motor 
for  the  second  outfit  for  their  own  use.  Others  go  a  step 


CONSTRUCTION  AND  OPERATION 


131 


farther  and  turn  a  good  business  in  this  way,  and  come 
in  for  a  fair  discount  from  our  prices  by  ordering  patterns 
or  frames  in  lots  of  a  half  dozen  at  a  time." 

Paper   Patterns. 

The  amateur  then  may  purchase,  from  a  concern  like 
that  mentioned  above,  simply  the  paper  patterns  and  do 


DeFoe  40'  and  50'   Cruisers. 

all  the  work  himself.  Remember,  these  patterns  are  not 
blue  prints  to  scale,  but  are  full  sized  patterns  for  every 
piece  in  the  boat. 

For  example,  you  are  given  a  full  sized  pattern  for  the 
keel.  This  you  lay  upon  your  plank  and  mark  out  the  keel. 
There  can  be  no  mistake.  In  the  same  way  you  cut  every 
piece  of  the  hull,  planking  and  all,  as  there  is  a  separate 
pattern  for  every  piece  and  every  plank. 

The  blue  print  idea  has  been  tried  and  found  wanting, 
as  it  naturally  would,  except  in  the  hands  of  a  skilled 


132  MOTOR  BOATS: 

mechanic  and  boatbuilder,  and  even  there,  it  is  claimed, 
it  falls  short  of  equaling  the  pattern  system. 

With  every  set  of  DeFoe  patterns  are  included  full  in- 
structions and  illustrations  for  doing  the  work.  These 
are  printed  on  a  large  sheet  of  paper  that  may  be  tacked 
against  the  wall  of  your  shop.  This  sheet  is  complete 
in  every  detail  and  worded  in  such  a  manner,  and  with 
the  illustrations  so  plain,  that  any  man  or  boy  can  work 
by-  it  without  the  slightest  trouble.  Remember,  this  is 
not  a  technical  sheet,  but  is  worded  in  the  simplest,  every- 
day language,  with  illustrations  that  could  not  be  mis- 
understood. 'This  -sheet  "contains  also  full  instructions 
for  painting  and  varnishing  and  all  finishing  work, -how 
to  mix  your  stains  and  fillers,  and  how.  to  put.  them_.gn' 
for  the  best  possible  results. 

The  Knocked-down  Frame  System. 

In  case  the  amateur  does  not  wish  to  do  all  the  work, 
he  can  purchase  the  knock-down  frame  with  which  pat- 
terns, instructions  and  illustrations,  to  complete  the  boat, 
an*  included,  without  extra,  cost. 

Some  boatbuilders  furnish  knock-down  frames  in  two 

grades — the.  Standard  frame  and  the  Special  frame. 

\ 

The  Standard  Frame. — In  this  frame  every  part  -is 
worked  to  shape.  Everything  is  dressed,  stem  and  stern 
knee  bolted  together  and  entirely  finished,  rabbet  and  all ; 
keel  is  finished  completely,  stem  and  stern  is  fitted  on, 
and  rabbet  worked  out ;  ribs  are  dressed  and  steam  bent. 
In  fact,  all  tool  work  is  done  on  the  frame  and  it  is  ready 
to, set  up.  They  do  not  set  this  frame  up  in  the  shops. 
When  the  purchaser  gets  it  he  sets  up  the  keel,  stem, 
stern,  and  molds,  and  fits  in  the  ribs,  and  is  then  ready  to 
put  on  the  planking.  This  is  by  far  the  most  popular 
frame,  partly  because  .of  tjhe  attractive  prices  quoted,  and 
also  because  freight  is  slightly  less  than  on  the  set-up 
frame.  If. the  amateur  is  not  pressed  for  time  he  will  be 


COXSTRUCTIOX  AXD   OPERATION  133 

just  as  well  satisfied  with  a  Standard  as  with  a  Special 
frame. 

The  Special  Frame. — This  is  a  finished  frame  in  every 
respect.  The  builders  set  it  up  in  the  shops,  finish  every 
item  of  tool  work,  fit  In  the  ribs  and  bevel  them  properly, 
put  on  the  top  plank  (or  sheer-strake)  and  bolt  in  the 
'clamps,  making  it  a  most  complete  frame.  Molds  or  rib- 
bands are  not  necessary  in  erecting  this  frame.  When 
the  purchaser  gets  it  he  uncrates  it  and  it  goes  together 
like  a  buggy  or, a  piece  of  machinery  that  comes  to  him 


DeFoe  Compromise  Stern  Launch  With  Hunting  Cabin. 

crated.  He  simply  puts  hi  the  bolts  and  screws  where 
the  builders  took  them  out.  These  frames,  if  under  20  ft. 
in  length,  can  be  shipped"  erected  if  so  ordered,  though 
freight  rates  will  be  somewhat  higher  than  if  the  frame 
is  knocked  down  and  crated. 

A  frame  consists  of  the  following  parts  with  all  tool 
work  done : 

Launches. — Stem,  keel,  stern,  and  deadwoods,  finished 
and  put  together ;  ribs  steam  bent,  clamps,  breast  hooks, 
deck  beams,  floor  timbers,  fenders,  keelson,  skeg  with 
pipelog  bored,  bolts  for  stems,  keel,  etc.,  together  with 
bill  of  materials,  patterns,  etc.,  for  completing  the  boat. 
In  Runabouts  the  transom  finished  complete  is  included. 

Canoes. — Keel,  stems,  gunwales,  fenderwales,  seat- 
risers,  seat  bars  and  decks. 


134  MOTOR  BOATS: 

Rowboats. — Stem  and  knee,  keel  plate,  skeg,  stern  post, 
transom  and  knee,  breast-hook,  gunwales,  fenderwales, 
risings,  ribs  and  oarlock  blocks. 

Sailboats. — Keel,  stem,  stem  knee,  transom,  m  transom 
knee,  trunk  logs  or  pocket-pieces,  head  ledges,  stern  post, 
skeg,  clamps,  deck  beams,  fenderwales  and  ribs. 

A  Special  frame  consists  of  all  parts  included  in  the 
Standard  frame  and  the  sheer-strake  additional,  set  up 
and  finished  as  stated  above. 

The  Bare  Hull. 

You  may  also  purchase  a  bare  hull.  The  builders  usu- 
ally carry  these  hulls  in  stock,  ready  for  completion.  The 
nails  are  not  set  and  they  are  not  faired  off,  as  this  is 
work  anyone  can  do,  and  the  average  -purchaser  would 
not  care  to  pay  for  having  it  done.  The  boat  yards  will 
do  it,  however,  at  a  slight  extra  cost.  The  clamps  and 
deck  beams  are  put  in.  This  is  an  attractive  offer  to 
many,  and  especially  to  the  amateur  who  wants  some- 
thing better  than  the  rest,  is  particularly  skilled  in  the 
use  of  tools  and  has  expert  knowledge  in  putting  on 
stains  and  varnishes.  You  can  purchase  a  perfect  hull, 
and  as  time  is  the  main  element  in  a  perfect  job  on  the 
top  and  interior  work,  you  may  by  the  use  of  fine  woods 
that  you  will  be  able  to  procure,  and  perhaps  a  few  orig- 
inal ideas,  turn  out  a  boat  that  will  be  the  pride  of  a 
sportsman's  heart. 

A  25-foot  compromise  stern  boat,  for  instance,  with  a 
cockpit  arranged  with  secret  drawers  and  cupboards,  an 
icebox,  a  gasolene  stove  of  one  burner  or  two,  secreted 
when  not  in  use  behind  a  movable  panel,  and  numerous 
other  devices,  products  of  your  own  ingenuity,  will  give 
you  an  outfit  that  will  yield  you  an  amount  of  satisfac- 
tion that  money  could  not  purchase  in  the  way  of  a  com- 
pleted boat  from  any  factory  in  the  land.  You  may  reach 
this  same  result  by  starting  with  patterns  alone,  or  a 


CONSTRUCTION  AND  OPERATION  135 

knock-down  frame ;  or,  if  you  wish  to  avoid  the  more 
difficult  parts  of  the  work,  get  the  bare  hull.  Freight  on  a 
bare  hull  would  be  at  the  same  rate  as  on  a  completed 
boat,  but,  of  course,  the  bare  hull  is  much  lighter  and 
freight  would  be  about  cut  in  two. 

If  you  order  coaming  from  the  boatbuilders  indi- 
cate which  wood  you  desire,  either  oak  or  birch.  If  a 
more  costly  wood,  such  as  mahogany  or  cherry,  is  or- 
dered, an  additional  charge  will  be  made,  depending  on 
the  size  of  coaming.  Either  oak  or  birch  is  the  standard 
wood  for  this  purpose. 

Bill  of  Materials. 

With  every  knock-down  frame  or  set  of  patterns  a  list 
of  all  hardware,  lumber,  etc.,  necessary  to  complete  the 
boat  is  usually  included.  The  builders  will  quote  you  a 
price  on  this  hardware  that  is  perhaps  better  than  you 
will  be  able  to  get  in  your  home  town,  unless  you  have 
the  advantage  of  extra  low  prices.  Hardware  of  iron  is 
sufficient  for  fresh  water;  for  salt  water  you  will  need 
hardware  of  galvanized  iron  or  of  copper  and  bronze. 


Ring  Buoy,  Steering  Wheel,  etc. 


136 


MOTOR   BOATS: 


Red  Wing  Auto  Boat— Red  Wing  Boat  Mfg.  Co., 
Red  Wing,  Minn. 


CHAPTER  XIII 

PRACTICAL  BOAT-BUILDING— Continued. 

2.     Form  and  Strength  of  Hull. 

The  general  principles  underlying  the  work  of  the  boat- 
builder  and  the  methods  whereby  these  principles  arc 
carried  into  effect,  are  not  difficult  to  comprehend. 

The  main  objects  of  the' builder  are  to  realize  the  de- 
sired form  and  to  provide  the  necessary  staunchness  and 
stability  in  his  craft.  In  other  words,  form  and  strength 
are  the  main  objects  to  be  attained. 

The  form  of  the  boat  is  a  matter  of  design  and  involves 
geometrical  principles  and  the  study  of  such  matters  as 
utility,  safety,  appearance  and  ,air  resistance.  The  ama- 
teur who  builds  his  boat  from  patterns  already  prepared 
for  him  has  little  or  nothing  to  do  with  the  matter  of 
design,  since  that  was  settled  for  him  when  he  chose  his 
model  and  bought  his  patterns.  To  realize  the  desired 
form,  he  has  simply  to  follow  the  patterns. 

The  provision  of  the  necessary  strength  in  a  boat  is, 
however,  a  matter  of  mechanics  and  involves  not  only  the 
selection  of  proper  materials  and  the  use  of  good  work- 
manship, but  the  observance  of  sound  mechanical  princi- 
ples to  overcome  the  strains  and  stresses  to  which  the 
beat  structure  will  be  subjected. 

There  are  secondary  matters,  of  course,  to  be  consid- 
ered before  the  boat  is  completed  for  use,  but  these  re- 
late mostly  to  the  boat  user's  convenience  or  comfort 
and  depend  a  good  deal  on  personal  taste.  It  is  unneces- 
sary to  dwell  on  these  secondary  matters,  which  may  be 
left  to  the  individual  boat-builder,  and  we  can  therefore 


138 


MOTOR  BOATS: 


confine  ourselves  here  to  the  realization  of  the  form  de- 
sired for  the  boat  and  the  provision  of  the  strength 
required. 

It  should  be  clearly  understood  that  while  these  main 
objects  are  separate  and  distinct,  they  must  be  regarded 
together  in  the  attainment  of  the  result  desired,  which 
is  to  realize  both  objects  with  the  same  set  of  structural 
members. 


Side  View 


Deck  Plan 

Compromise  Stern  Motor-Boat. 
(Racine  Boat  Co.) 

The  actual  form  of  the  surface  of  the  hull  depends  en- 
tirely upon  the  outer  planking  or  skin.  To  assemble  this 
planking  in  the  form  desired  an  inner  frame  of  some  kind 
is  necessary,  over  which  the  planking  may  be  bent  and 
secured  in  shape,  also  some  form  of  internal  stiffening 
to  assist  the  planking  in  preserving  the  desired  shape. 

Thus,  we  must  have  these  three  factors  in  boat  con- 
struction : 

(1)  An  internal  straightening  framework. 

(2)  Frames  or  molds  over  which  the  planking  is  bent 
to  the  desired  form. 

(3)  The  outer  skin  or  planking. 


CONSTRUCTION  AND  OPERATION  139 

In  practical  boat-building  two  different  methods  of 
construction  are  employed.  The  first  is  a  common  method 
of  building  small  craft,  such  as  rowboats  and  the  smaller 
motor-boats  and  launches.  In  this  method  the  frames 
over  which  the  planking  is  bent  are  temporary  wooden 
molds  and  their  object  is  fulfilled  when  the  planking  is 
put  together  in  the  proper  form  for  the  outer  skin  of  the 
boat. 

In  the  second  method,  used  for  the  larger  motor-boats, 
a  framework  composed  of  various  members,  including 
frames  and  cross  ties  or  deck  beams,  is  first  constructed 
and  set  up  to  form  a  sort  of  skeleton  of  the  boat  model 
desired.  The  planking  is  then  bent  over  and  secured  to 
this  framework  to  form  the  outer  skin  and  the  framework 
thereupon  becomes  an  integral  part  of  the  boat. 

In  building  a  boat  from  knock-down  frames,  as  de- 
scribed elsewhere,  these  frames  when  set  up  constitute 
the  permanent  framework  referred  to  above  and  it  is  no 
inconsiderable  part  of  the  entire  construction  of  the  boat. 
In  other  words,  the  use  of  knock-down  frames  saves  the 
amateur  builder  most  of  the  heavy  carpenter  work,  be- 
sides assuring  him  of  securing  the  form  desired. 

We  may  call  the  first  method  of  boat-building  the  mold 
method  and  the  second  the  frame  method,  it  being  clearly 
understood  that  molds  are  for  temporary  use  only,  to 
determine  the  form  of  the  planking,  while  frames  form  a 
permanent  part  of  the  boat  structure. 

Provision  of  Required  Strength. 

In  providing  the  necessary  strength  for  the  boat  hull, 
it  is  well  to  remember  that  strength  is  required  in  three 
different  respects,  namely,  Longitudinally,  transversely 
and  locally. 

Longitudinal  strength  may  be  defined  as  the  capacity  to 
resist  bending  along  the  fore  and  aft  lines  of  the  boat, 
such  as  hogging  or  sagging  of  the  hull  as  a  whole. 


140 


MOTOR  BOATS: 


Transverse  strength  is  the  ability  of  the  structure  to  re- 
sist bending  or  distortion  to  right  or  left  with  reference 
to  the  fore  and  aft  axis, — in  other  words,  to  resist  trans- 
verse strain  or  the  strain  produced  in  the  planking  or 
other  member  by  a  force  operating  at  right  angles  to  its 
length. 

Local  strength  is  the  capacity  of  the  various  members 
of  the  hull  to  resist  stress  exerted  at  any  particular  point ; 
that  .is,  such  a  stress  as  might  injure  the  hull  at  that 
point,  but  might  not  produce  any  distortion  of  its  general 
lines. 

In  a  boat  without  permanent  frames  or  internal  brac- 
ing, the  'planking  is  the  principal  factor  which  secures 
longitudinal  strength.  Various  supplementary  factors 
are  required,  however,  to  secure  the  necessary  stiffness 


of  the  hull  as  a  whole  and  these  may  include  the  combi- 
nation of  the  keel  and  keelson,  the  sheer  strake,  stringers, 
clamps,  and  fender  pieces  or  strips.  The  various  posi- 
tions in  which  these  appear  are  illustrated.  They  are 
not  usually  all  found  in  any  one  boat,  though  some  are 
common  to  all  designs.' 

In  the    provision  of  transverse  strength  the  planking 
with  its  internal  framing  forms  the  principal  factor,  thus 


CONSTRUCTION  AND  OPERATION  141 

serving  a  double  purpose,  namely,  determining  the  form 
or  shape  of  the  boat  and  providing  a  good  deal  of  the 
strength  required  in  the  structure.  The  top  sides  of  the 
boat,  which  are  the  weakest  parts  of  the  hull,  may  be 
strengthened  by  the  use  of  deck  beams  or  stringers, 
which  prevent  the  sides  from  opening  outward  or  col- 
lapsing inward,  either  of  which  by  changing  the  form 
of  the  boat  would  destroy  its  general  effectiveness. 
Where  deck  planking  is  used  this  adds  to  the  transverse 
strength  as  opposed  to  inward  strain.  Though  this  plank- 
ing is  not  often  relied  upon  for  the  purpose,  it  likewise 
adds  to  the  longitudinal  strength  of  the  boat  and  may  be 
regarded,  therefore,  as  one  of  the  factors,  though  not  an 
important  one,  contributing  to  the  general  stiffness  of 
the  decked  hull.  The  flooring  laid  in  the  boat  likewise 
contributes  its  share  to  the  transverse  strength,  giving 
additional  stiffness  along  the  keel  and  bottom  of  the  boat 
and  forming  a  support  for  the  lower  members  when  these 
are  subjected  to  transverse  stress. 


Turbine  Boat — Shallow  Draft. 

As  far  as  local  strength  of  the  various  members  of 
the  hull  is  concerned,  butlittle  special  .'attention  is  usually 
required  apart  from  the  use  of  good  materials,  especially 
sound  timber.  Near  the  bow,  however,  where  the  sides 
of  the  boat  may  come  in  contact  with  the  dock  or  other 
craft,  also  beneath  the  engine  and  at  the  stern  where  the 
propeller  shaft  requires  support,  special  construction  is 
needed  to  secure  local  strength  at  these  points. 


142 


MOTOR  BOATS: 


At  the  bow  of  the  boat  and  in  other  points  local 
strength  is  usually  secured  by  means  of  chock  or  angle 
pieces,  as  will  be  seen  in  our  illustrations  showing  longi- 
tudinal sections  of  motor  boats.  The  sides  of  the  boat 
may  be  strengthened  by  means  of  special  fender  pieces 
or  strips.  The  part  of  the  boat  beneath  the  engine  is 
strengthened  to  perform  its  duty  usually  by  a  special 
foundation  of  longitudinal  timbers  or  of  steel,  attached 
to  the  structure  of  the  boat  in  such  a* way  as  to  distribute 
through  the  hull  the  local  stresses  occurring  through  the 
running  of  the  engine. 

The  methods  in  use  for  this  purpose  are  clearly  indi- 
cated in  the  chapter  devoted  to  the  installation  of  engines. 
Generally  speaking,  it  may  be  said  here  that  the  engine 
foundation  should  be  long  and  large  enough  not  only  to 
provide  the  local  strength  required,  but  also  to  distribute 
the  stresses  properly. 


Red  Wing  16'  Runabout. 


CHAPTER  XIV 

PRACTICAL  BOAT-BUILDING— Continued. 

3.     Structural  Members  and  Materials. 

In  the  construction  of  small  power  boats  and  launches 
of  wood,  the  following  are  the  structural  members  re- 
quired in  ordinary  practice  and  the  materials  commonly 
employed  for  each  member. 

Keel — Usually  of  oak,  of  square  or  nearly  square  sec^ 
tion  for  the  older  standard  form  of  stern;  sometimes 
rectangular  with  the  greater  dimension  vertical.  A  flat 
keel  is  dsed  for  the  torpedo  boat  stern,  which  is  a  more 
modern  form  of  construction. 

Stem — Commonly  of  oak  and  fitted  to  the  keel  with 
knees  of  oak  or  hackmatack  (the  American  larch  or  tam- 
arack). When  the  sternpost  is  fitted  to  the  keel,  the 
same  method  and  materials  are  used. 

Frames — Also  commonly  of  oak  from  y2  inch  to  1  inch 
square  and  set  from  6  to  9  inches  apart  (between 
centers),  the  size  and  spacing  depending  upon  the  size 
of  the  boat  and  varying  in  accordance  with  the  character 
of  the  construction. 

Deck  Beams — These  are  usually  of  oak,  though  spruce 
or  sometimes  pine  is  used,  and  must  be  spaced  to  suit 
the  frames.  Their  size  may  vary  in  section  with  the  size 
and  character  of  the  construction  from  l/2  to  1  inch  wide 
by  1  to  2  inches  deep. 

Planking — The  side  planking  for  boats  of  small  size 
may  be  of  cypress,  cedar  or  pine,  and  either  a  single  or 
double  set  of  planking  may  be  used,  varying  in  thickness 
from  a  mere  shell  %  inch  thick  to  1  inch  or  even  more. 


144  MOTOR   BOATS: 

according  to  the  size  of  the  craft  and  character  of  con- 
struction. Mahogany  is  also  sometimes  used  for  the 
side  planking.  Ordinarily  a  single  layer  of  planking 
from  %  to  \y%  inches  thick  is  good  practice,  where  it 
is  not  necessary  to  regard  the  weight  of  the  structure. 
This  constitutes  a  serviceable  and  perhaps  the  least  ex^ 
pensive  form  of  construction.  In  this  form  of  outer  skin 
for  the  boat,  the  seams  must  be  carefully  attended  to  and 
calking  and  painting  are  also  points  that  need  looking 
after. 

A  better  water-tight  construction  is  secured  by  the  use 
of  2  layers  of  planking,  each  from  %  to  l/2  inch  thick, 
having  white  lead  between,  and  care  being  taken  that  the 
joints  of  the  two  layers  do  not  come  together. 

In  building  high  speed  boats  special  planking  of  cedar 
or  mahogany  in  layers  about  l/4  inch  thick  is  used,  of  ton 
with  a  layer  of  oiled  or  varnished  silk  or  other  fabric  be- 
tween the  layers  of  wood. 

Deck  Planking — Is  usually  of  cedar  or  pine  y%  to  Y^ 
inch  thick,  often  waterproofed  with  a  canvas  covering 
laid  in  white  lead  or  varnish. 

Fastenings — The  fastenings  used  in  boats  of  wood  may 
be  copper  rivets  and  burrs,  copper  nails  clinched  or  riv- 
eted over  burrs,  screw  fastenings  of  various  kinds,  plain 
galvanized  iron  nails  and  ordinary  screws.  In  the  best 
practice  for  first  class  work,  all  fastenings  are  of  copper, 
brass,  or  bronze  and  these  are  "through  and  through" 
fastenings  instead  of  being  merely  driven  into  the  wood. 

Bulkheads — In  modern  construction  of  first  class  boats 
it  is  usual  to  divide  the  hull  into  water-tight  compart- 
ments by  means  of  bulkheads.  It  is  evident  that  these, 
in  order  to  be  water-tight,  must  be  designed  and  fitted 
with  the  utmost  care  and  must  possess  considerable 
strength.  Several  such  compartments  are  found  in  the 
best  models,  especially  for  seagoing  craft,  and  the  object 


CONSTRUCTION  AND  OPERATION  145 

is  usually  to  provide  that  the  boat  will  float  when  any 
single  compartment  is  rilled  with  water — and  also  sup- 
port the  occupants  of  the  boat. 

Xo  matter  what  the  size  of  the  boat,  the  question  of 
providing  water-tight  compartments  is  an  important  one. 
Boats  so  fitted  give  the  owners  and  occupants  a  com- 
fortable sense  of  security,  adding  greatly  to  their  pleas- 
ure in  the  use  of  the  boat.  It  is  sometimes  difficult  to 
find  room  for  such  compartments'  at  the  bow  and  stern 
of  the  ordinary  boat  with  open  cockpit,  particularly  when 
plenty  of  seating  capacity  in  the  cockpit  is  required,  but 
to  secure  safety  under  all  circumstances,  especially  in 
case  of  emergency  or  accident,  it  is  well  to  cut  down  or 
limit  the  size  of  the  open  cockpit,  so  as  to  enable  com- 
partments to  be  provided  at  the  bow  and  stern  by  means 
of  water-tight  bulkheads,  and  these  compartments  should 
be  large  enough  to  enable  a  boat  to  float,  even  if  the 
cockpit  is  filled  with  water. 

The  necessity  for  water-tight  compartments  is  of  course 
less  in  boats  intended  for  use  in  shallow,  smooth  waters 
than  in  craft  used  on  the  seaboard,  deep  lakes  or  large 
rivers,  but  the  matter  should  be  always  carefully  con- 
sidered. It  is  satisfactory  to  note  that  in  the  best  mod- 
ern practice  the  provision  of  water-tight  compartments 
of  sufficient  size  to  float  the  boat  under  all  possible  con- 
tingencies is  regarded  as  being  of  the  first  importance. 
Very  often,  of  course,  the  highest  possible  degree  of 
safety  can  be  secured  without  sacrificing  a  single  other 
feature  of  utility  in  the  design  of  the  boat. 

Typical  Material  Specifications. 

The  following  are  typical  specifications  for  the  ma- 
terials used  in  moderate  speed  motor  boats  of  18  to  30 
feet  in  length : 

Frame — Keel  and  keelson  of  solid  white  oak,  one  piece, 
white  oak  natural  crook  stem,  securely  fastened  to  keel. 

Solid  oak  stern.     Frames  of  clear,  straight-grained  white 
lo 


146 


MOTOR  BOATS: 


S-f 

• 


CO  3 

.s  ° 
°.s 

•4-> 

o 


CONSTRUCTION  AND  OPERATION  147 

oak,  spaced  closely  together.  Extra  heavy  frames  at 
motor  foundation  to  strengthen  and  reduce  vibration. 

Decking — Coaming,  guard  rail,  covering  boards  of 
clear,  finely  figured,  white  oak.  Decks  of  quarter-sawed 
white  oak,  finished  natural  or  canvas  covered. 

Trimming — Combination  bow  chock  and  flagstaff 
socket.  Cleats,  chocks,  deck  sheaves,  stern  flagstaff 
socket,  brass  nickel  plated.  Steering  wheel  at  bow,  brass 
nickel  plated  and  mahogany.  Wire  tiller  line  runs  through 
brass  nickel-plated  sheaves  and  leaders. 

Planking — Clear,  red  cypress,  cedar  or  white  pine.  The 
garboard  and  sheerstrakes  are  of  clear  white  oak,  put  on 
in  long  lengths,  fastened  to  frames  with  brass  screws  or 
copper  rivets.  All  holes  in  both  planking  and  frames  are 
bored  to  prevent  cracking. 

Cockpit — Entire  cockpit  sealed  up  with  white  oak  or 
cedar,  fastened  with  copper  nails.  Seats  on  sides  and 
across  at  stern  end  of  cockpit.  Lockers  under  all  seats. 
Fronts  from  seat  to  floor  nicely  paneled.  Lids  on  all 
seats,  fastened  with  brass  hinges,  to  make  all  such  space 
under  seats  useful  for  storage. 

Finish — The  entire  boat  is  sanded  to  a  smooth  surface 
and  given  a  coat  of  hot  linseed  oil.  Over  this  are  ap- 
plied three  coats  of  copper  paint  below  water  line. 
With  three  coats  of  pure  white  enamel  marine  paint 
above  to  sheerstrake,  the  entire  interior  with  frames  is 
treated  to  one  coat  of  linseed  oil,  put  on  hot,  and  twc, 
coats  of  pure  red  lead  paint.  Sheerstrake,  fenders,  cover- 
ing boards,  decks,  coaming  and  interior  of  entire  cockpit 
finished  natural  in  three  coats  of  best  spar  varnish  above 
filler. 

Construction  of  High  Speed  Boats. 

There  is  a  wide  difference  in  practice  when  we  come 
to  the  construction  of  motor-boats  designed  exclusively 
for  speed.  The  high  speed  racing  machines  are  so  con- 


148  MOTOR  BOATS: 

structed  as  to  realize  the  main  object  of  their  design  with 
the  minimum  of  weight  in  the  hull  and  engine. 

In  the  high  speed  boat  the  frames  are  comparatively 
smaller  in  section  than  in  the  ordinary  moderate  speed 
runabout.  The  material  must  be  carefully  selected.  The 
frames  are  also  set  somewhat  closer  together  than  in  the 
ordinary  boat,  in  order  to  offset  the  reduction  in  thick- 
ness of  the  side  planking  and  the  consequent  lessening  of 
local  strength.  This  reduced  spacing  involves  an  in- 
crease in  the  number  of  the  frames,  but  with  proper  de- 
sign and  the  reduction  in  section  of  the  frames  there  may 
be  an  important  saving  of  weight  in  the  hull  as  com- 
pared with  the  ordinary  method  of  construction. 

The  side  planking  of  high  speed  boats  is  usually  fitted 
in  two  layers,  each  about  l/4  inch  thick.  Occasionally 
only  a  single  layer  is  used  and  the  seams  are  covered  on 
the  inside  of  the  boat  with  strips,  which  also  serve  the 
purpose  of  stringers.  Where  this  method  is  employed, 
calking  is  not  necessary  and  the  weight  of  the  hull  is 
considerably  reduced.  Careful  workmanship  is  required 
in  such  construction. 

Special  bracing  is  sometimes  worked  into  the  structure 
of  high  speed  boats,  this  being  placed  diagonally  inside 
the  frames.  •  It  adds  to  the  transverse  strength  of  the 
hull,  supporting  it  against  torsional  stress  and  consol- 
idating the  framework  into  a  structure  best  suited  to 
withstand  the  vibration  caused  by  the  working  of  a 
powerful  high  speed  engine. 

In  other  cases  of  special  construction  for  racing  craft 
light  girders  are  worked  along  the  interior  sides  of  the 
hull  to  give  additional  longitudinal  strength.  These 
girders  may  include  top  and  bottom  chords,  timber  struts 
and  steel  wire  braces.  They  add  but  little  to  the  total 
weight  and  increase  the  resistance  of  the  hull  to  longi- 
tudinal stresses. 


CONSTRUCTION  AND  OPERATION  149 

In  many  notable  cases,  special  forms  of  framing  have 
been  used  for  racing  boats.  These  have  usually  been 
designed  with  the  object  of  saving  weight  in  the  hull.  A 
typical  case  of  special  framing  is  thus  described  by 
''Marine  Engineering:"  "The  length  of  the  boat  over 
all  is  60  feet  and  on  the  water  line  48  feet,  with  an  ex- 
treme beam  of  7  feet  6  inches.  The  planking  is  of  single 
thickness  Honduras  mahogany  3-16  inch  thick,  ajid  with 
edges  secured  by  flush  screws  to  continuous  longitudinals 
of  Oregon  pine.  The  framing  is  carried  out  on  a  special 
double  system  consisting'  of  inner  and  outer  frames  and 
longitudinals.  The  longitudinals  are  notched  over  the 
outer  frames,  and  all  three  parts  of  the  structure  are 
through  riveted,  giving  great  transverse  strength  on  a 
minimum  of  weight.  The  inner  frame  is  furthermore 
carried  continuous  up  the  side  and  across,  forming  the 
lower  member  of  the  deck  beam,  while  the  upper  member 
of  the  same  runs  across  from  side  to  side  and  ends  at  the 
planksheer.  The  longitudinal  strength  of  the  boat  is  ob- 
tained chiefly  from  two  truss  girders  running  from  end 
to  end  in  the  wings,  and  consisting  of  upper  and  lower 
continuous  longitudinals,  wooden  compression  struts 
and  galvanized  wire  diagonals  set  up  tight." 

The  local  stiffening  provided  for  high  speed  boats  is 
also  reduced  as  compared  with  that  used  in  the  ordinary 
moderate  speed  boat,  but  this  is  done  at  a  sacrifice  of  a 
certain  amount  of  safety  in  this  respect  and  only  after 
careful  design,  so  as  to  secure  the  greatest  possible 
strength  of  the  least  possible  weight. 

The  forms  of  special  construction  briefly  indicated 
above  have  resulted  in  producing  boats  in  which  the  hull 
has  about  one-third  the  total  displacement  of  water  after 
trie  engine  is  installed  as  compared  with  the  weight  of  the 
hull  in  ordinary  boats  of  one-half  to  two-thirds  the  total 
ultimate  displacement. 


150  MOTOR  BOATS: 

Typical  Specifications. 

The  following  are  typical  specifications  for  a  high 
speed  motor-boat: 

Frame — Keel  and  keelson  of  solid  white  oak,  one  piece, 
white  oak  natural  crook  stem,  securely  fastened  to  keel. 
Solid  oak  stern.  Frames  of  clear,  straight  grained  white 
oak,  spaced  closely  together.  Extra  heavy  frames  at 
motor  foundation  to  strengthen  and  reduce  vibration. 

Planking — Clear  red  cypress,  cedar  or  white  oak  The 
garboard  and  sheerstrakes  are  of  clear  white  oak,  put  on 
in  long  lengths,  fastened  to  frames  with  brass  screws 
or  copper  rivets.  All  holes  in  both  planking  and  frames 
are  bored  to  prevent  cracking. 

Decking — Coaming,  guard  rail  and  covering  boards  of 
clear,  finely  figured  white  oak.  Decks  of  quarter-sawed 
white  oak. 

Cockpit — Entire  cockpit  sealed  up  with  white  pine  or 
cypress,  fastened  with  copper  nails.  Seats  on  sides  and 
across  at  stern  end  of  cockpit. 

Steel  Boats. 

Very  many  motor-boat  hulls  are  now  built  of  steel 
In  this  form  of  construction  the  general  characteristics 
are  similar  to  those  found  in  wooden  construction.  The 
framing  includes  longitudinal  keel  plate  and  stringer 
angles,  transverse  angle  iron  frames,  deck  beams  and 
steel  plating,  the  latter  being  fitted  similarly  to  the  plank- 
ing of  wooden  craft. 

All  these  members  of  the  framing  of  steel  boats  fulfill 
the  same  general  functions  as  the  similar  members  in 
wooden  hulls. 


CHAPTER  XV 

PRACTICAL  BOAT-BUILDING— Continued. 
4.     Laying  Down  and  Assembling — Finishing. 

The  process  of  assembling  the  structural  members  of 
a  boat  may  now  be  considered.  First,  however  (unless 
modern  full-sized  boat  patterns  are  used),  the  water  lines 
and  sections  at  each  frame  must  be  laid  down  full  size. 
This  is  done  on  the  floor  of  the  amateur  builder's  shed  or 
loft  and  chalk  marks  are  usually  employed  for  the  pur-, 
pose,  these  being  often  done  over  with  black  lead  to  pre- 
vent rubbing  out.  The  lines  are  taken  from  the  designer's 


Lines  of  a  Dory  Launch. 

plans,  including  the  half-breadth  body  and  sheer  plans, 
but  are  made  full  size,  all  proportions  being  duly  ob- 
served. The  sections  when  transferred  to  the  floor  will 
indicate  the  sectional  form  at  various  stations  to  be  regu- 
larly measured  off  along  the  line  of  the  keel.  These 
should  be  numbered  for  convenience. 

It  should  be  noted  whether  the  lines  of  the  design  re- 
late to  the  outside  of  the  frame  or  to  the  actual  water  sur- 


152 


MOTOR  BOATS: 


face  of  the  boat.  If  the  latter,  the  thickness  of  the  plank- 
ing must  be  deducted  all  along  the  section  lines  in  order 
to  obtain  proper  form  for  the  frame. 

If  the  boat  is  to  be  built  with  fixed  molds,  after  laying 
down  the  lines  we  must  next  determine  the  form  of  the 
molds.  At  least  five  such  molds  are  required  between 
the  stem  and  stern  post  and  it  will  often  be  found  ad- 
vantageous to  use  not  less  than  eight  molds  for  boats  of 
small  size.  A  series  of  twelve  molds  is  frequently  used 
for  a  small  launch. 


M/DSH/P 


SECT/ON 


The  form  of  each  mold  is  obtained  from  the  full-size 
sections.  A  'single  board  of  sufficient  width  is  used  to 
form  one-half  of  the  mold.  A  duplicate  of  this  being 
made,  the  two  are  placed  together  to  form  the  complete 
mold. 

To  obtain  the  form  of  the  half  section  on  the  board 
used  for  the  purpose,  nails  may  be  laid  down  with  their 
heads  on  the  section  line  and  the  bodies  at  right  angles 
thereto,  the  board  being  then  gently  laid  down  upon  the 
nails  and  tapped  with  a  hammer  or  pressed  upon  them. 
An  imprint  of  the  nail  heads  will  thus  be  made  on  the 
under  side  of  the  board  and  it  will  then  be  an  easy  matter 
to  reproduce  the  form  of  the  half  section  on  the  board  by 
means  of  a  batten  sprung  through  the  continuous  im- 
prints of  the  nail  heads. 


CONSTRUCTION  AXD  OPERATIOX 


153 


The  half  of  the  mold  is  then  cut  along  the  lines  in- 
dicated. The  vertical  section  lines  having  been  noted, 
the  duplicate  half  is  cut  and  the  two  may  be  joined  in  the 
manner  indicated  in  the  illustration,  with  a  cross-pawl  or 
horizontal  piece  of  timber  at  the  top. 


Joinel 


The^rest  of  the  molds  are  made  in  a  similar  way,  until 
the  entire  series  is  complete.  They  are  then  ready  to 
be  assembled  on  the  keel,  and  we  may  proceed  to  prepare 
the  keel. 

To  support  the  keel  a  two-inch  plank  should  be  set  up 
on  end  and  blocked  securely.  The  upper  edge  must  be 
cut  or  trimmed  to  correspond  with  the  design  for  the 
sweep  of  the  keel.  This  supporting  plank  forms  no  part 
of  the  boat  structure,  but  is  simply  a  convenient  founda- 
tion for  the  work.  If  this  support  is  adjusted  in  such  a 
manner  as  to  bring  the  intended  water  line  of  the  boat 
horizontal  with  reference  to  the  floor  of  the  shed  or  loft, 
it  will  be  found  a  great  convenience  to  the  builder. 

A  pattern  for  the  stem  is  taken  from  the  floor  in  the 
same  way  as  the  form  of  the  molds  is  secured,  and  it  may 
be  noted  here  that  while  the  molds  are  on  the  floor,  the 
height  of  the  deck  line,  if  any,  and  the  load  water  line 
should  be  marked  on  them. 


154  MOTOR  BOATS: 

The  keel,  stem  and  stern  posts  should  now  be  pre- 
pared according  to  the  dimensions  required  and  must  be 
rabbeted  to  admit  the  edge  of  the  garboard  strake,  or 
first  range  or  strake  of  planks  laid  on  the  bottom  of  the 
hull  next  to  the  keel,  and  its  ends  at  the  stern  and 
stem.  They  are  then  erected  in  turn  on  the  keel  support 
and  the  stem  and  stern  posts  are  secured  to  the  keel  by 
means  of  chocks  and  fastenings  through  and  through. 

For  the  stem  a  white  oak  plank  may  be  used,  cut  to 
shape  of  the  pattern.  A  center  line  should  be  scratched 
along  its  face  and  also  another  line  on  each  side  of  this 
to  show  width  of  the  face  when  finished.  The  thickness 
of  the  stem  usually  tapers  to  the  point  where  it  joins  the 
keel.  -Position  of  the  load  water  line  taken  from  the  body 
plan  should  be  scratched  across  the  face  of  the  stern. 

The  stem  and  stern  knees  should  be  cut  as  shown  on 
the  plan  and  bolted  to  the  stern  with  Y$  inch  galvanized 
bolts,  care  being  taken  to  set  the  bolts  at  cross  angles 
across  the  scarf  to  draw  the  stem  and  knee  together.  It 
the  boat  is  to  be  fitted  with  the  old  form  of  stern  the 
deadwood  and  shaft-log  may  next  be  cut  to  dimensions 
and  fitted  to  place.  The  deadwood  is  a  body  of  timber 
built  up  on  top  of  the  keel  to  afford  a  firm  fastening  for 
the  planks  rising  obliquely  from  the  keel.  The  shaft-log 
must  be  of  clear,  straight-grained  oak,  having  a  longi- 
tudinal hole  cut  through  its  center  of  a  size  suitable  to 
accommodate  the  shaft  tube.  It  is  usually  formed  by  a 
couple  of  timbers  bolted  together  with  galvanized  iron 
bolts. 

In  assembling  all  these  members  of  the  structure  care 
should  be  taken  to  see  that  the  joints  between  timbers 
are  perfectly  tight.     They  should  be  treated  with  white 
lead  and  closed  with  "through  and  through"  fastenings. 
Erecting  the  Molds. 

The  next  step  is  to  erect  the  section  molds,  made  in 
the  manner  already  described.  After  placing  them  at  the 


CONSTRUCTION  AND  OPERATION  155 

proper  stations,  which  should  be  marked  at  regular  in- 
tervals on  the  keel,  they  must  be  centered  and  squared 
up  with  the  keel  and  then  fastened  in  place  securely  by 
means  of  braces  and  ties. 

Each  mold  should  be  carefully  plumbed  fore  and  aft 
and  sideways  before  being  braced  in  place.  A  straight 
edged  board  several  inches  wide  should  then  be  nailed  on 
the  center  line  of  the  cross-pawls,  one  edge  being  just 
at  the  center  line.  By  means  of  this  straight  edge,  each 
mold  can  be  squared  athwartship  and  should  be  nailed 
at  the  top  to  a  batten  extending  longitudinally  around  the 
molds  from  stem  to  stern.  To  insure  the  molds  being 
plumb  sideways,  a  spirit  level  may  be  set  on  top  of 
each  ^cross-pawl  to  see  that  it  is  level  from  side  to  side. 
Then  the  mold  can  be  braced  securely  from  above  on  each 
side. 

The  molds  having  been  secured  in  place,  we  may  now 
proceed  to  put  in  the  ribbands. 

These  are  strips  of  wood  bent  over  the  molds  and 
fastened  to  them  from  stem  to  stern  along  the  lines  of 
the  planking.  They  help  to  retain  the  molds  in  place, 
and  when  fitted  will  also  serve  to  show  any  defects  in  the 
lines  of  the  hull.  The  molds  should  be  of  sufficient  height 
to  allow  the  upper  ribband  to  be  fixed  above  the  point 
designed  for  the  sheer  strake  and  thus  serve  to  support 
the  frame  until  the  sheer  strake  and  clamp  piece  are  in 
place. 

The  ribbands  may  also  be  made  large  enough  and 
numerous  enough  to  enable  the  frames  to  be  bent  in 
against  them  to  the  proper  form.  This,  however,  is  only 
done  in  the  case  of  small  boats. 

Bending  in  the  Frames. 

Bending  in  the  frames  will  be  the  next  operation.  The 
material  for  these  should  be  carefully  selected  and  extra 
pieces  should  be  provided,  as  some  are  likely  to  break  in 


156  MOTOR  BOATS: 

bending.  A  good  material  is  tough  clear  white  oak.  In 
order  to  make  the  frame  timbers  bend  evenly,  they  should 
be  made  of  uniform  thickness  by  being  run  through  a 
planer  after  being  sawed  out.  As  already  stated,  small 
frames  may  be  bent  directly  to  the  required  form  against 
the  ribbands,  but  usually  the  frame  after  being  properly 
sized,  must  be  first  steamed.  It  is  then  taken  immediately 
to  its  place,  bent  in  to  the  required  form,  then  secured  to 
the  keel,  clamped  to  the  ribbands  and  carefully  adjusted 
in  the  proper  position. 

For  the  purpose  of  steaming  frame  timbers,  a  steam  box 
is  required.  This  may  be  about  14  inches  square  and  12 
feet  long.  It  can  be  made  from  common  pine  boards, 
well  cleated  on  the  outside  and  one  end  closed  tight. "  The 
other  end  is  left  open  to  receive  the  frames,  but  when  in 
use  is  closed  by  a  temporary  door  or  even  by  a  bundle 
of  rags  stuffed  in  tight.  In, order  that  the  frames  may 
be  set  in  the  hottest  steam,  slats  should  be  fixed  across 
the  inside  of  the  box  and  the  frames  placed  on  them. 
An  ordinary  wash  boiler  with  a  tight  wooden  cover  will 
give  plenty  of  steam  and  it  can  be  taken  to  the  box 
through  an  iron  pipe  or  rubber  tube.  Frames  should  be 
steamed  about  an  hour  and  the  steam  should  not  be  al- 
lowed to  go  down,  but  should  be  kept  hot  until  the  frames 
come  out.  See  Steam  Box  in  following  chapter. 

For  larger  boats,  when  the  frames  can  not  easily  be  bent 
in  against  the  ribbands,  they  are  usually  formed  on  a 
bending  floor  or  by  means  of  frame  molds.  When  they 
are  formed  on  the  floor  the  exact  shape  of  the  frame  on 
the  inner  or  concave  side  is  laid  down  on  the  floor.  Pegs 
.  or  nails  are  driven  into  the  floor  along  the  line  of  the  de- 
sign and  the  steamed  frame  is  then  bent  to  the  required 
shape  against  these  pegs  or  nails.  Sometimes  special 
molds  are  cut  for  each  frame  and  with  this  as  a  founda- 
tion the  frame  is  bent  to  form. 


CONSTRUCTION  AND  OPERATION 


15' 


Whenever  the  shape  of  the  frame  will  permit,  it  should 
run  in  one  continuous  piece  from  rail  to  rail  without  any 
joint  at  the  keel,  but  this  can  apply  only  to  the  frames  in 
the  midship  section  of  the  boat.  Nearer  the  stem  and 
stern,  where  the  angles  at  the  keel  are  sharp,  the  frame  is 
necessarily  bent  in  in  two  parts,  these  being  secured  to- 
gether by  a 'chock  at  the  bottom.  When  bent  to  form, 
either  as  one  continuous  piece  or  in  two  parts,  however, 


25'  Trunk  Cabin  Cruiser. 
(Racine  Boat  Co.) 

the  two  'sides  of  the  frame  are  firmly  secured  by  cross 
ties,  so  that  when  erected  in  the  hull,  it  will  retain  its 
form. 

When  in  place  at  the  proper  station  on  the  keel,  each 
frame  should  be  permanently  fastened  thereto,  with  a 
temporary  fastening  to  the  ribbands  by  clamps.  The 
heel  of  the  frame  may  be  fastened  to  the  keel  by  two 
galvanized  wire  nails,  which  should  be  bored  for  and  have 
their  heads  countersunk.  The  fastenings  to  the  keel  will 
include  the  fitting  of  chocks  and  bent  floors  with  keelson, 
the  latter  being  a  continuous  strip  running  fore  and  aft, 
securely  fastening  the  flooring  to  the  keel.  The  floors, 
which  may  be  of  one-inch  timber,  are  usually  fitted  to 


158  MOTOR  BOATS: 

the  shape  of  the  frames  and  notched  closely  over  the 
keel.  They  must  extend  high  enough  to  reach  to  the 
bottom  of  the  cabin  or  cockpit  floor,  which  is  fastened 
to  them,  and  they  may  be  bolted  to  the  keel  with  ^  inch 
galvanized  bolts  and  riveted  to  the  frames  with  two 
rivets  on  each  side. 

Limbers  must  be  cut  in  them  and  these  should  be  of 
sufficient  size  to  prevent  them  clogging  up,  small  ones  be- 
ing of  little  use.  For  the  benefit  of  the  novice,  it  may 
be  stated  that  these  "limbers"  are  holes  cut  through  the 
floor  timbers  to  permit  the  draining  of  water  to  the  bilge 
or  pump  well. 

When  the  frames  are  well  set,  the  molds  can  be  taken 
out,  care  being  taken  before  doing  this  work  on  the 
frames  which  are  the  height  of  cross-pawls,  to  put  stay 
laths  across  at  each  mold,  well  fastened  to  the  upper 
battens,  and  transfer  the  overhead  braces  to  the  stay 
laths. 

Planking  and  Seating. 

The  skeleton  of  the  hull  being  now  set  up,  it  is  ready 
for  the  planking  or  outer  skin.  This  should  be  prepared 
in  lengths  as  long  as  possible,  each  plank  being  tapered 
toward  the  bow  and  stern,  so  that  there  may  be  the  same 
number  of  strakes  from  stem  to  stern.  The  edges  of  the 
planking  will  then  come  as  nearly  as  possible  at  right 
angles  to  the  frames. 

If  the  method  of  construction  involves  a  double  layer 
of  planking,  the  outer  layer  should  be  so  arranged  that 
the  joints  will  not  correspond  with  those  of  the  inner 
layer.  After  the  inner  layer  is  put  on,  its  outer  surface 
may  be  painted  thickly  with  white  lead,  special  care  be- 
ing taken  to  cover  the  end  joints  and  seams.  If  the  joints 
and  seams  of  the  second  or  outer  layer  of  planking  are 
also  similarly  painted  or  covered,  it  will  help  to  make 
the  skin  perfectly  water-tight. 


CONSTRUCTION  AND  OPERATION 


159 


•  Before  fitting  the  longitudinal  planks,  the  ribbands  for- 
merly noted  must  be  removed  with  the  exception  of  the 
topmost  ribband,  which,  as  we  have  stated,  should  be 
sufficiently  high  to  clear  the  sheer  strake  and  clamp  piece. 
When  the  planking  has  progressed  as  far  as  the  sheer 
strake,  the  latter  is  carefully  fitted.  This  covers  the  top- 
most strake  of  planking  and  is  securely  fastened  to  the 
frames  and  the  construction  strengthened  by  means  of 
the  clamp  piece  or  longitudinal  member  on  the  inner  side 
of  the  frames,  the  whole  being  firmly  bolted  together. 


30'   Raised  Deck  Cruiser.     . 
(Racine  Boat  Co.) 

The  upper  ribband  may  now  be  removed,  after  a  few 
ties  have  been  run  across  from  one  side  of  the  hull  to  the 
other.  The  tops  of  the  frames  are  then  cut  off  and  the 
molds,  if  still  standing,  are  removed. 

The  rail  is  then  finished  and  may  be  made  with  a  cap 
piece  to  cover  the  sheer  strake,  clamp  and  space  between 
them  formed  by  the  frame  ends ;  or  the  space  between  the 
frames  may  be  filled  in  flush  with  the  sheer  strake  and 
clamp  pieces;  or  the  combination  of  sheer  strake,  clamp 
and  frame  ends,  may  be  left  to  form  the  rail. 

In  most  cases,  bilge  and  side  stringers  should  be  put 
on  to  add  to  the  longitudinal  strength  of  the  hull. 


160  MOTOR   BOATS: 

With  regard  to  the  foundation  for  the  engine,  complete 
instructions  will  be  found  in  the  section  devoted  to  in- 
stallation of  engines.  Details  of  this  work  depend  alto- 
gether upon  the  size,  weight  and  design  of  the  engine. 

As  already  stated,  however,  care  should  be  taken  to 
put  in  a  foundation  of  sufficient  size  and  length  to  dis- 
tribute the  stresses  caused  by  the  operation  of  the  engine 
as  far  as  possible  throughout  the  hull. 

Seating — In  order  to  support  the  seats  called  for  by  the 
boat  design,  whether  these  are  fore  or  aft  or  across  the 
boat,  suitable  stringer  pieces  are  fitted  on  the  inside  of 
the  frames  and  securely  fastened  to  them.  The  seats 
being  carefully  fitted  and  fastened  to  these  stringers, 
will  add  to  the  strength  of  the  structure,  acting  as  braces 
for  the  side,  especially  in  the  case  of  transverse  seats, 
which,  when  properly  fitted,  add  greatly  to  the  lateral 
strength  of  the  hull,  preventing  compression  of  the  sides 
or  bulging  as  the  case  may  be. 

Fore  and  aft  seats,  when  properly  fitted,  add  to  the 
longitudinal  strength  of  the  sides,  as  well  as  increasing 
the  transverse  strength.  When  fore  and  aft  seats  are 
fitted,  their  inner  edge  is  supported  on  posts  standing  on 
and  fastened  to  a  stringer  piece  secured  to  the  frames. 

Chocks  or  brackets  may  alsoxbe  fitted  under  the  seats 
to  add  to  the  strength  of  the  construction. 

If  the  boat  is  to  be  decked  or  partially  decked,  the  next 
step  is  to  put  in  the  deck  beams  and  then  the  deck  plank- 
ing ov^r  the  space  to  be  covered. 

If  gasolene  tanks  or  air  tanks  are  to  be  installed  be- 
neath decks,  these  must,  of  course,  be  set  in  place  before 
the  space  is  finally  closed. 

Finishing  the  Exterior. 

When  the  work  of  construction  has  reached  this  stage, 
the  exterior  of  the  hull  is  ready  for  planing  and  finishing. 
The  first  step  is  to  rough  plane  the  planking  and  then  to 


CONSTRUCTION  AND  OPERATION  161 

calk  and  fill  the  joints  carefully  with  thick  white  lead 
or  other  suitable  material ;  then  the  entire  exterior  can  be 
finally  planed,  smoothed  up  and  prepared  for  painting 
and  puttying. 

In  the  case  of  single  planked  boats  with  a  thin  skjn, 
great  care  must  be  taken  in  the  final  planing  not  to 
weaken  the  structure  by  removing  too  much  of  the  sur- 
face of  wood,  as  the  thickness  of  the  timber  will  not 
stand  it.  Judgment  must  be  used  in  such  cases,  in  order 
to  secure  the  best  results  in  the  form  of  the  finished  ex- 
terior without  sacrificing  the  strength  of  the  structure. 

It  will  readily  be  seen  at  this  point  that  special  care 
must  be  taken  in  all  the  earlier  stages  of  the  work,  so 
as  to  secure  the  precise  form  designed.  Hence,  at  every 
stage,  especially  in  preparing  the  molds  and  frames,  di- 
mensions must  be  carefully  observed  and  workmanship 
must  be  exact,  in  order  to  secure  the  form  required.  After 
the  frames  are  in  and  the  planking  fitted,  it  is  too  late 
to  correct  any  error  in  the  external  lines  of  the  boat  and 
this  fact  should  be  borne  in  mind  from  the  moment  of 
laying  .down  the  keel. 

If  the  boat  has  been  built  on  approved  lines  with  care- 
ful attention  to  details  of  workmanship  and  design,  the 
exterior  of  the  hull  will  emerge  from  the  operations  of 
planing,  scraping  and  sand  papering  in  a  form  to  delight 
the  eye  of  the  builder. 

When  double  planking  is  fitted,  the  operation  of  calk- 
ing is  not  always  necessary,  but  in  the  case  of  thick 
planking  it  is  usually  best  to  calk.  The  operation  of 
calking  is  the  driving  of  cotton  or  oakum  into  the  seams 
with  a  calking  iron,  or  broad  form  of  chisel  and  a  mallet, 
in  order  to  prevent  the  penetration  of  water.  The  oakum 
or  cotton  is  forced  below  the  surface  by  means  of  the 
iron.  In  the  construction  of  large  boats  and  in  shipbuild- 
ing, the  seams  are  usually  covered  with  melted  pitch. 


162  MOTOR  BOATS: 

With  thin  planking,  less  than  half  an  inch  thick  for 
instance,  the  seams  would  hardly  retain  the  cotton, 
hence,  when  the  thinner  forms  of  planking  are  used,  it  is 
necessary  to  use  it  in  two  layers  with  shifted  seams,  this 
construction  obviating  the  necessity  of  calking.  White 
lead  is  freely  used  to  protect  the  seams. 

Painting — Care  should  be  taken  to  use  only  the  best 
kinds  of  marine  paint.  Three  or  four  coats  can  be  given, 
each  coat  being  rubbed  down  before  the  next  is  applied, 
and  plenty  of  time  being  allowed  for  drying  between 
coats.  If  this  is  properly  done,  the  result  will  be  a 
smooth,  hard  surface  of  lasting  quality. 

A  typical  course  pursued  by  boat-builders  in  finishing 
is  as  follows :  The  entire  boat  is  sanded  to  a  smooth  sur- 
face and  given  a  coat  of  hot  linseed  oil.  Over  this  are 
applied  three  coats  of  copper  paint  below  water  line. 
With  three  coats  of  pure  white  enamel  marine  paint  above 
to  sheer  strake,  the  entire  interior,  with  frames,  is  treated 
to  one  coat  of  linseed  oil,  put  on  hot,  and  two  coats  of 
pure  red  lead  paint.  Sheer  strake,  fenders,  covering 
boards,  decks,  coaming  and  interior  of  entire  cockpit  are 
finished  natural  in  three  coats  of  best  spar  varnish  above 
filler. 


In  the  above  we  have  referred  particularly  to  the  con- 
struction of  small  boats  and  launches  made  over  molds 
with  the  old  form  of  stern  and  deadwood. 

In  the  construction  of  larger  boats  of  the  same  gen- 
eral design,  the  frames  are  heavier  and  stiffer  in  pro- 
portion and  being  molded  or  bent  to  form  on  the  floor 
after  steaming,  the  use  of  molds  is  unnecessary. 

The  keel,  stem  and  stern  posts  are  set  up  in  the  manner 
described  above  and  the  frames  being  then  erected  in 
place  and  ribbands  fastened  along  the  sides,  the  boat  is 
"in  frame"  and  the  further  steps  of  construction,  including 


CONSTRUCTION  AND   OPERATION 


163 


planking,  decking,  seating  and   finish,  are  conducted  in 
the  same  general  way  as  in  building  smaller  boats. 

\Yhen  a  more  modern  form  of  stern  is  adopted  in  the 
design,  such  as  the  well-known  torpedo  stern,  the  various 
steps  of  construction  are  practically  the  same  as  in  the 
older  model,  but  the  keel  is  usually  a  flat  timber,  rather 
than  square  as  in  the  old  style  boat.  Provision  also  has  to 
be  made  to  support  the  shaft  tube  and  shaft  properly 
where  these  pass  through  the  bottom  of  the  boat.  Sup- 
ports must  be  provided,  not  only  for  the  shaft  bearing  at 
the  point  of  passage  through  the  bottom,  but  also  at  the 
point  where  the  shaft  emerges  into  the  water,  just  for- 
ward  of  the  propelle'r.  This  may  be  in  the  form  of  a 
steel  or  bronze  bracket  securely  fastened  to  the  stern 
to  support  the  shaft  bearing. 


Launch  Equipped  With  7  H.  P.  Clifton  Engine. 

It  being  impossible  within  the  scope  of  a  work  of  this 
size  to  describe  in  detail  all  the  varied  processes  required 
in  the  building  of  the  innumerable  models  now  seen  in 
American  waters,  we  have  endeavored  to  give  a  general 
practical  idea  of  the  methods  of  procedure  commonly  em- 
ployed in  building  boats  and  launches  of  types  generally 


164 


MOTOR  BOATS: 


regarded  as  normal,  and  designed  for  moderate  speed  and 
cruising  purposes.  At  the  same  time  we  have  shown  the 
peculiar  forms  of  construction  used  in  building  speed 
craft,  such  as  the  special  methods  of  framing,  the  use  of 
extra  thin  planking,  sometimes  with  varnished  silk  or 
other  fabric  between  layers,  and  other  features  tending 
to  secure  the  rigidity  of  structure  required  where  light- 
weight, high-speed  engines  are  installed. 

Our  description  of  the  methods  commonly  employed 
will  suffice  to  start  any  amateur  who  possesses  a  slight 
knowledge  of  carpentry  on  the  right  road  to  success  in 
building  his  own  boat. 

Equipped  with  the  knowledge  furnished  in  the  pre- 
ceding chapters,  he  will  be  stimulated  to  an  intelligent 
study  of  the  plans  from  which  his  boat  is  to  be  con- 
structed and  will  know  how  to  set  about  the  routine 
of  operations  required  in  all  boat  construction. 

Specific  instructions  for  the  building  of  a  typical  power 
boat  from  patterns  will  be  found  in  detail  in  the  next 
chapter,  and  these  will  furnish  any  points  that  may  not  be 
included  in  the  general  outline  of  operations  already 
given. 


Under  Water  Exhaust. 
(Outing  Boat  Co.) 


CHAPTER  XVI 

PRACTICAL  BOAT  BUILDING— Continued. 

5.     How  to  Build  a  Boat  from  Patterns. 

Complete  instructions  for  building  from  paper  pat- 
terns a  motor  boat  or  launch  from  16  to  30  feet  or  more 
in  length  are  given  in  the  following  pages.  A  typical 
boat  for  a  novice  to  build  would  be,  say,  an  18-footer  of 
standard  stern,  about  4  feet  2  inches  beam,  designed  to 
carry  six  or  eight  persons  and  to  run  8^/2  or  9  miles  an 
hour  when  equipped  with  a  3  H.  P.  motor. 

The  necessary  patterns  (or  knock-down  frames,  if  de- 
sired) for  building  such  a  boat  or  indeed  a  launch  of 
any  size  or  style  can  be  obtained  from  the  boat-builders 
who  make  a  specialty  of  such  business.  The  instruc- 
tions and  forms  of  design  given  in  the  various  sections 
of  this  chapter  apply  particularly  to  the  patterns  fur- 
nished by  the  DeFoe  Boat  &  Motor  Works,  of  Bay 
City,  Michigan,  where  the  pattern  system  originated. 

Section  1. — How  to  Handle  Patterns. 

If  the  sheets  are  large  and  unwieldy  cut  them  up  into 
convenient  sizes,  taking  care  not  to  cut  the  lines  of  any 
pattern.  Lay  the  pattern  you  wish  to  use  on  your  ma- 
terial, hold  it  carefully  in  place  with  weights  or  tacks, 
and  trace  the  lines  with  a  tracing  wheel,  bearing  on  suf- 
ficiently to  leave  the  imprint  on  the  wood.  Remove  the 
pattern  and  cut  out  the  piece.  Be  careful  to  leave  enough 
wood  outside  the  pattern  lines  so  that  the  piece  will 
smooth  up  to  the  exact  size  of  the  pattern. 

Another  method  is  as  follows :  Prick  holes  through  on 
the  lines  of  the  pattern  with  an  awl.  Make  them  about  18 


166 


MOTOR   BOATS: 


CONSTRUCTION  AND  OPERATION  167 

inches  apart  on  lines  slightly  curved  and  from  that  to 
very  close  together  on  lines  greatly  curved.  Remove 
the  pattern,  stick  nails  into  the  awl  holes,  bend  a  thin 
batten  along  the  nails  and  mark  the  line  by  it. 

Be  careful  to  use  your  material  to  the  best  advantage, 
and  cut  the  parts  out  in  a  way  to  leave  the  least  waste. 
You  can  make  a  big  difference  in  the  cost  of  your  boat 
in  this  way. 

In  placing  your  pattern  on  the  wood  be  careful  that 
the  grain  runs  in  the  proper  direction  to  give  the  greatest 
strength.  For  example,  the  grain  in  the  breast-hook 
(Fig.  6)  should  run  crosswise,  in  the  transom-knees 
(Fig.  3)  diagonally,  etc. 

Do  not  cut  your  paper  patterns  out  to  exact  size,  as  a 
long  narrow  pattern,  such  as  a  plank  pattern  for  ex- 
ample, would  be  apt  to  lose  its  shape.  It  is  a  good  plan, 
after  each  part  is  finished,  to  place  it  on  the  pattern 
again  and  see  that  no  mistakes  have  been  made.  Do 
this  every  time  without  fail.  . 

Section  2. — Materials  to  Use. 

All  lumber  should  be  well  seasoned  and  air-dried 
rather  than  kiln-dried,  as  kiln-drying  makes  it  brittle. 

White  oak  is  by  far  the  best  material  to  use  for  the 
frame-work  of  the  boat.  Rock  elm  may  be  used.  Fir 
-may  be  used  for  stem,  keel,  etc.,  but  it  will  not  bend 
for  ribs. 

For  planking  use  white  pine,  cypress,  or  cedar  if  it 
can  be  obtained  and  it  generally  can.  Southern  pine  may 
be  used,  but  it  splits  easily  and  is  difficult  to  work  and  to 
hold  in  place.  Avoid  basswood,  poplar,  etc.,  unless  your 
boat  is  to  be  canvas  covered,  as  they  will  not  stand  the 
water.  Fir  or  spruce  may  be  'used. 

Buy  good  lumber.  Wide  boards  cut  with  less  waste 
than  narrow  ones.  Cross-grained,  knotty  or  shaky  stuff 
will  split  and  you  will  waste  more  in  working  it  up  than 
you  will  save  on  the  lower  price. 


168 


MOTOR  BOATS: 


Section  3. — Keel,  Stem,  Stern-post  and  Skeg. 

Keel — The  first  part  to  construct  is  the  keel.     Using 

patterns  as  directed,  cut  the  keel  to  shape,  and  if  made 

of  two  pieces   (as  in  the  larger  boats),  fasten  together 

with  a  butt  splice  (Fig.  2  a).    The  keel  is  now  finished. 


FIG.  2. 

Stern — First  saw  out  stem  and  stem-knee  from  the 
patterns,  and  bolt  them  together  as  shown  in  Fig.  2  (b). 
Mark  the  rabbet  line  on  both  sides,  and  with  a  chisel  cut 
the  groove,  called  the  rabbet,  as  shown  in  Fig.  2  (c). 
The  ends  of  the  plank  are  to  be  fitted  into  the  rabbet, 
and  hence  it  should  be  as  deep  as  the  plank  is  thick. 


CONSTRUCTION  AND   OPERATION 


169 


Cut  the  rabbet  with  plenty  of  bevel  as  shown  in  Fig.  2 
(d),  so  that  the  plank  will  slip  in  easy.  The  rabbet  line 
and  bearding  line  are  shown  on  the  stem  pattern.  In 
compromise  stern  boats  the  stern-post  is  put  together 
and  rabbeted  exactly  as  the  stem. 


FIG.  3. 

Fig.  3  (a)  shows  construction  of  the  transom  stern. 
(For  torpedo  and  fantail  stern  construction  special  in- 
struction sheet  is  sent.) 


170  MOTOR  BOATS: 

The  skeg  is  made  of  stuff  two  to  four  inches  thick, 
depending  on  size  of  boat.  Have  it  thick  enough  that 
there  is  plenty  of  room  for  the  shaft  hole,  though  not  so 
thick  as  to  be  cumbersome.  If  you  haven't  the  means 
of  boring  the  shaft  hole  rip  the  skeg  in  two  on  the  line 
of  the  shaft  and  gouge  out  the  shaft  hole.  Then  fasteri 
the  two  pieces  together  again  by  means  of  a  flat  cheek 
piece  screwed  firmly  on  each  side.  Fig.  3  (b).  Fit  this 
piece  on  carefully  and  bed  it  in  white  lead  and  you  will 
never  be  troubled  with  leaks.  The  stern  post  is  put  in 
to  make  a  better  fastening  for  the  shaft  bearing,  as  the 
screws  would  not  hold  in  the  end  of  the  timber  of  the 
skeg.  The  figure  shows  how  to  fasten  stern  post  to 
skeg  and  put  in  stopwaters.  Paint  the  skeg  and  keel 
where  they  are  to  be  joined  and. lay  a  thin  sheet  of 
rubber  or  canvas  between  them  to  prevent  leaks,  and 
fasten  skeg  to  keel  by  nailing  down  through  keel.  Nail 
thoroughly,  boring  a  small  hole  for  the  nails  to  prevent 
splitting. 

A  stopwater  is  a  small  pine  plug  driven  into  a  hole 
bored  for  it,  to  prevent  a  leak  in  a  spot  that  cannot  be 
reached  to  calk.  Fit  them  carefully  and  they  will  swell 
enough  to  prevent  the  leak.  A  little  study  of  the  illus- 
tration will  show  you  just  why  they  are  put  in  certain 
places. 

Section  4. — Setting  Up  Frame. 

Molds — The  next  step  is  to  make  the  molds.  They 
may  be  made  out  of  any  rough  cheap  stuff,  as  they  are 
not  a  part  of  the  boat,  but  simply  forms  to  build  it  over. 
Wide  boards  will  work  up  handier.  Fig.  4  shows  two 
molds.  The  pattern  of  but  half  the  mold  is  given.  Cut 
out  one  half  of  the  mold  and  use  it  to  mark  the  other 
half  by.  Get  -the  distance  across  the  top  from  the  pat- 
tern, and  also  mark  the  center  of  each  mold. 


CONSTRUCTION  AND  OPERATION 


171 


Next,  from  a  two-inch  plank  8  to  12  inches  wide,  con- 
struct a  long  horse  for  the  purpose  shown  in  Fig.  1. 
Malte  it  straight  on  top,  and  nail  the  legs  to  the  floor  so 
as  to  brace  it  straight  in  line.  Compromise  and  torpedo 
stern  boats  draw  more  water  forward  than  aft  and  it  is 


FIG  4. 

better  to  raise  the  horse  on  longer  legs  at  the  stern  end 
so  that  the  boat  will  set  while  building  about  as  it  is 
supposed  to  set  in  the  water.  The  builder  can  then  better 
judge  of  his  work  while  he  is  building. 

Bolt  the  stem  and  stern-post  and  skeg  to  the  keel, 
place  the  whole  on  the  horse  and  fasten  keel  down  to 
the  horse  so  that  it  will  be  in  line,  that  is  with  no  kinks 
or  bends  in  it.  ' 

Fasten  the  molds  to  the  keel  (keel  pattern  shows 
where  they  belong)  by  nailing  a  block  on  the  keel  and 
the  molds  to  this  block.  Fasten  them  square  across  the 
keel  and  perpendicular  to  it.  Nail  a  board  with  a  straight 
edge  (splice  two  together  if  need  be)  from  stem  to  stern 
on  top  of  the  molds,  bringing  the  center  line  of  the  mold 
to  this  straight  edge,  Fig.  1.  This  is  to  hold  the  mold 
square  across  the  keel  and  perpendicular  to  it. 

Plumb  up  the  stem  and  stern  with  a  plumb  bob,  and 
brace  the  whole  thing  either  to  the  roof  or  floor  as  shown 
in  Fig.  1.  . 


172 


MOTOR   BOATS: 


The-  sheer  strake  is  the  top  plank  of  the  boat  and  the 
sheer  line  is  the  top  line  of  this  plank.  The  top  of  each 
mold  will  just  come  to  the  sheer  line  if  you  make  them 
exact  size  of  pattern  and  the  point  where  the  rabbet  line 
ends  on  the  stems  is  the  sheer  line. 

Next  put  on  the  ribbands.  These  are  narrow  strips 
of  straight  grained  stuff  free  from  knots,  about  ^"x%" 
for  small  boats  to  %"x%"  for  larger  ones.  Put  at  least 
five  ribbands  on  each  side,  screw  them  to  the  stem  and 
stern  and  nail  them  with  light  nails  to  the  molds. 
Neither  molds  nor  ribbands  are  a  part  of  the  boat,  but 
are  simply  used  for  putting  in  the  ribs. 

Section  5. — Bending  and  Putting  in  the  Ribs. 

Everything  is  now  ready  for  the  ribs.  These  are  to 
be  steamed  and  bent  over  a  form,  or  forms,  and  allowed 
to  cool  before  using.  It  is  generally  best  to  use  two  or 
three  different  bending  forms,  as  the  ribs  do  not  all  have 
the  same  bend  in  them.  Make  these  forms  out  of  a  piece 
of  "fa"  board,  and  use  the  molds  for  patterns.  It  is  not 


FIG.  5. 


CONSTRUCTION  AND  OPERATION 


173 


necessary  to  make  a  form  from  every  mold,  but  select 
the  mold  with  the  greatest  bend  and  one  or  two  others. 
Make  the  form  so  that  the  rib  will  have  a  little  more 
bend  than  the  mold,  as  it  will  spring  back  a  little  after 
it  is  bent.  And  it  is  a  simple  matter  to  straighten  it 
farther  if  it  does  not  spring  back  enough.  Nail  these 
forms  down  to  the  bench. 

Procure  a  piece  of  thin  band  iron  about  the  width  of 
the  rib  and  bend  a  hook  in  one  end  that  will  just  fit  over 
the  end  of  the  rib,  Fig.  5  (a),  Steam  the  ribs  thoroughly 
for  an  hour.  Clamp  the  iron  strap  quickly  on  a  hot  rib 
as  shown  in  Fig.  5  (a),  and  immediately  bent  it  around 
the  bending  form  as  in  Fig.  5  (b).  Tack  a  stay  lath 
across  to  keep  it  from  straightening  out  and  the  iron 
strap  may  then  be  removed,  the  rib  taken  off  the  form, 
and  the  operation  repeated  on  the  next  rib.  Leave  the 
ribs  about  an  hour  until  they  are  thoroughly  cooled. 


FIG.  6. 

Then  the  stay-lath  may  be  knocked  off  and  the  rib  is 
ready  for  use.  Be  careful  that  each  rib  touches  every 
ribband  or  the  outside  of  your  boat  will  not  be  smooth. 
Fit  the  lower  end  to  the  keel,  nail  it  fast,  boring  for  the 
nail  through  the  rib  to  prevent  splitting  it,  and  tack  them 
temporarily  to  the  ribbands.  Cut  ribs  5  or  6  inches 


174  MOTOR  BOATS: 

longer  than  required  length  to  be  sure  of  a  fit.  Be  sure 
to  get  the  bend  in  the  proper  place,  so  that  one  end  of  the 
rib  will  not  be  too  short.  The  ribs  near  the  stems  must 
be  notched  into  the»sides  of  the  stem  knee,  as  shown  in 
Fig.  6. 

Floor  Timbers — Figures  1  and  6  show  floor  timbers. 
They  are  used  to  fasten  the  ribs  together  and  to  fasten 
them  more  firmly  to  the  keel.  Use  oak  about  the  thick- 
ness of  the  ribs  and  about  \l/2  to  3  inches  deep.  Lay 
the  piece  alongside  the  ribs  and'  mark  it.  Then  take  it 
out  and  cut  it  to  shape.  In  this  way  a  good  fit  can  be 
very  easily  obtained.  Nail  it  firmly  to  ribs  and  to  keel. 
Be  sure  to  cut  a  limber  hole  in  each  one  to  let  water  run 
back  to  pump.  Put  a  floor  timber  on  every  other  rib. 
It  is  scarcely  necessary  to  put  them  on  every  rib.  The 
molds  may  be  in  the  way  of  some  of  the  ribs.  If  so,  put 
these  ribs  in  after  the  molds  are  taken  out. 

Be  very  careful  to  do  all  this  work  exactly  to  the  pat- 
terns, for  if  your  molds  are  not  made  correct  in  size  and 
placed  correctly,  and  if  the  ribs  are  not  fitted  exactly  to 
the  ribbands,  of  course  the  plank  patterns  will  not  fit. 
Section  6. — Planking. 

The  plank  patterns  are  marked  and  numbered  as  fol- 
lows: They  are  numbered  1,  2,  3,  4,  etc.,  up  from  the 
keel,  No.  1  being  the  plank  next  to  the  keel.  This  plank 
is  called  the  garboard.  No.  2  is  the  next  plank  above 
and  so  on.  In  large  boats  each  plank  will  probably  be  in 
two  or  three  pieces.  The  end  of  the  piece  that  goes  to- 
ward the  bow  is  marked  with  an  X  and  the  pieces  of  a 
plank  are  lettered  from  the  bow.  For  example  consider 
the  12th  plank  on  a  30-foot  boat  (see  Fig.  1).  You  will 
find  that  it  is  in  three  pieces.  One  piece  is  numbered  X, 
12,  A,  the  X  meaning  that  this  end  points  toward  the 
stem,  the  12  that  it  is  the  12th  plank  from  the  keel,  a.nd 
the  A  that  it  is  the  first  piece  of  the  plank  toward  the 
bow.  The  next  piece  is  marked  X,  12,  B,  the  X  and  12 


CONSTRUCTION  AND  OPERATION  175 

indicating  same  as  before,  and  the  B  that  this  is  the  2nd 
piece  of  the  plank  from  the  bow.  In  shorter  boats  this 
plank  would  be  in  but  two  pieces.  The  proper  edge  of 
the  plank  is  up  when  the  number  and  letters  on  the  pat- 
terns are  right  side  up  as  the  boat  sets  on  her  keel.  Be 
sure  to  get  the  proper  edge  up.  Mark  the  upper  edge 
as  you  take  the  pattern  off  the  board.  The  first  strake 
of  plank  to  be  put  on  is  the  sheerstrake  (See  Figs.  1 
and  6).  Place  the  top  edge  even  with  the  top  of  the 
molds  and  where  the  rabbet  line  ends  on  stem  and  stern- 
post  (or  top  of  transom  in  square  stern  boats).  Most 
builders  prefer  to  finish  this  in  natural  wood.  In  such 
a  case  all  screws  and  bolts  should  be  plugged.  (See 
section  on  Painting,  Varnishing  and  Finishing.)  Screw 
the  top  edge  to  the  ribs  (as  shown  in  Figs.  6  and  1). 
The  bottom  is  not  necessarily  fastened  until  clamp  is 
put  in  (see  section  7).  In  putting  on  any  strake  fit  up 
and  nail  to  the  stem  and  stern  first,  then  splice.  (Fig.  6). 

As  each  piece  of  plank  is  got  out  and  fitted,  use  it  as 
a  pattern  to  cut  a  like  piece  for  the  other  side  of  the 
boat.  Be  very  careful  to  finish  up  both  pieces  the  same 
size,  so  that  both  sides  of  boat  will  be  exactly  alike. 

Fig.  6  shows  method  of  splicing  plank.  The  plank 
patterns  are  all  made  about  6  inches  longer  than  the 
finished  plank  is  to  be,  to  allow  for  sawing  for  the  splice. 
Xail  both  pieces  to  the  ribs  except  for  the  two  or  three 
ribs  near  the  splice,  and,  holding  the  saw  square  across, 
saw  both  pieces  off  at  once.  •  This,  of  course,  leaves  the 
two  pieces  fitting  perfectly,  the  saw  cut  leaving  a  space  of 
about  1-16  inch  between  them  to  allow  for  calking. 
Make  butt  blocks  (Fig.  6)  of  oak,  as  it  will  hold  the  nails 
well,  and  make  them  about  the  thickness  of  the  ribs. 
Xail  plank  to  both  butt  blocks  and  ribs  from  the  outside 
with  clout  nails  that  will  reach  through  and  clinch.  If 
sheerstrake  is  to  be  varnished,  screw  to  butt  blocks  and 
plug  screw.  When  the  sheerstrake  is  on,  put  on  the  rest 


176  MOTOR  BOATS: 

of  the  plank  down  to  the  bilge  (i.  e.,  where  the  bend 
comes  in  the  ribs).  Then  the  most  convenient  method 
is  to  turn  the  boat  Qver,  horse  and  all,  (leaving  the  horse 
on  will  keep  the.  keel  in  line)  plumb  up  the  stem  and 
stern,  and  put  on  the  plank  next  to  the  keel,  called  the 
garboard.  This  is  the  most  difficult  plank  to  put  on  and 
takes  some  careful  fitting.  Then  plank  from  both  ways, 
leaving  about  the  3rd  plank  from  the  keel  to  go  on  last. 
This  plank  is  called  the  shutter.  Unless  your  work  has 
been  very  accurately  done  the  pattern  for  this  piece  will 
not  be  apt  to  fit.  It  is  safest  anyway  to  cut  it  larger 
than  the  pattern  and  then  dress  it  down  to  fit.  The  only 
object  in  turning  the  boat  over  is  to  make  it  handier  to 
work  at.  If  you  prefer  you  may  plank  it  entirely  right 
side  up. 

Fig.  6  shows  two  methods  of  holding  plank  to  place 
and  closing  the  seams  tight  while  nailing.  The  chain 
clamp  may  be  purchased  of  the  pattern  makers.  The 
other  method,  though  serviceable,  is  not  as  convenient. 
It  often  requires  quite  a  pressure  to  make  these  seams 
tight.  They  should  come  up  tight  on  the  inside,  but  the 
edges  should  be  beveled  before  putting  on,  so  that  the 
seam  will  be  open  about  l-16th  of  an  inch  on  the  outside 
to  allow  the  calking  to  be  driven  in.  (See  section  on 
Calking.)  'After  the  plank  is  sawn  out  dress  up  the 
edges  with  a  plane,  and  hold  it  up  in  place  to  see  that  it 
fits.  At  the  same  time  bevel  the  edges  a  little  to  allow 
for  the  calking  seam. 

The  planks  that  go  on  the  bilge  must  be  hollowed  out 
a  little  on  the  inside  to  fit  the  curve  of  the  ribs.  This  is 
easiest  done  with  a  round  bottom  plane.  If  you  haven't 
a  round  bottom  plane,  gouge  out  with  your  chisel  where 
the  rib  goes,  till  you  get  a  fit. 

With  few  exceptions  all  planks  will  go  on  without 
steaming. 


CONSTRUCTION  AND  OPERATION  177 

Section  7. — Clamps  and  Breast-hooks. 

When  planks  are  all  on  remove  the  horse  from  the 
keel,  right  the  boat  up,  and  take  out  the  forms.  Place 
the  boat  at  any  convenient  height  for  work,  plumb  up  the 
stem  and  stern,  and  brace  in  position. 

The  clamps  (Fig.  6)  are  located  just  the  width  of  the 
deck  beams  below  the  top  of  the  sheerstrake.  They  are 
straight  pieces  (preferably  oak)  and  are  sprung  into 
place.  They  should  be  about  l/2  the  width  of  the  sheer- 
strake, and  from  %  inch  thick  in  16-foot  boats  to  about 
1  %  inches  in  30-foot  and  35-foot  boats.  They  are  bolted 
through  every  rib,  the  same  bolt  fastening  lower  edge  of 
sheerstrake,  Fig.  6. 

The  breast-hooks  (Fig.  6)  are  of  oak,  with  the  grain 
running  crosswise,  and  rest  on  top  of  the  clamps.  Bolt 
and  screw  them  in  as  shown  in  illustration.  Make  them 
thick  enough  that  they  will  dress  down  even  with  the 
sheerstrake  so  that  the  deck  will  lie  flat  on  top  of  them. 
Place  breast-hook  in  stern  also  of  compromise  launches. 

The  keelson  is  shown  in  Fig.  6.  Have  your  floor  tim- 
bers level  so  that  keelson  will  lie  flat  on  top  of  them.  A 
%  piece  about  the  width  of  keel  should  be  used.  Fasten 
securely  at  stem-knee  and  stern,  and  to  every  floor  tim- 
ber, as  this  is  the  main  strength  of  the  boat.  A  keel  and 
keelson  construction  such  as  this  is  immeasurably 
stronger  than  a  solid  keel  piece  such  as  some  builders 
use,  and  absolutely  prevents  vibration. 

Decks — But  one  deck-beam  pattern  is  given,  as  this  is 
sufficient.  Cut  deck  beams  to  required  length  and  get 
the  shape  from  this  pattern,  since  the  curve  will  of 
course  be  the  same  in  each  beam.  Deck  beams  are  nailed 
on  top  of  clamps  and  along  side  of  a  rib  (Fig.  6)  where  a 
secure  fastening  may  be  made.  Before  nailing  them  in 
be  sure  the  boat  is  spread  out  to  proper  width,  accord- 
ing to  forward  mold  which  you  have  removed.  Nail 
deck  knees  (Fig.  7)  in  a  little  high  and  then  shape  down 


178 


MOTOR  BOATS: 


even  with  deck  beams  so  that  decks  and  covering  board 
lie  level.  It  is  best  for  the  amateur  to  cut  a  true  circle 
for  the  coaming,  as  the  coaming  will  then  go  in  much 
easier.  A  few  trials  with  a  pencil  and  string,  as  shown 
in  Fig.  7,  will  get  the  proper  center.  Strike  the  circle  to 
come  exactly  tang-ent  to  the  covering  board,  for  if  there 
is  a  short  jog  here  the  coaming  cannot  be  brought  up 
to  fit. 


FIG.  7. 

Place  the  deck  beams  from  about  6  inches  apart  in 
smaller  boats  to  about  10  inches  in -'larger  ones.  The 
distance  apart  of  deck  beams  may  depend  also  on  thick- 
ness of  decking  used.  Decking  should  be  from  ^2  to 
34  inch. 

Fig.  7  shows  a  method  for  putting  on  deck  for  a  var- 
nish finish.  Put  on  partner  piece  first,  then  covering 
boards.  Put  little  blocks  of  proper  height  on  the  clamp 
along  the  sides  to  hold  the  covering  board. 


CONSTRUCTION  AND  OPERATIOX  179 

If  you  wish  you  may  make  the  partner  piece  from  3-16 
to  ]/4  of  an  inch  thicker  than  the  rest  of  the  deck,  letting 
it  project  above  the  rest  of  the  deck  this  much.  Cut 
the  covering  boards  to  shape.  Xail  the  short  pieces 
marked  (a)  Fig.  7,  between  the  deck  beams,  and  flush 
with  them  to  hold  the  ends  of  the  decking.  Begin  to 
put  the  decking  on  at  the  partner  piece,  and  fill  out  to  the 
covering  board.  This  deck  should  be  calked.  Hence, 
leave  seams  opken  about  1-16  inch  at  the  top  and  close 
them  tight  at  the  bottom.  Calk  with  a  cotton  cord.  Be 
careful  to  get  these  seams  all  true  and  even.  Set  the 
nails.  Plane  the  deck  smooth  and  scrape  it  before  put- 
ting on  coaming.  Careful  \vork  is  necessary  for  a  good 
job  on  this  deck,  but  it  can  be  done  by  anyone  who  will 
take  plenty  of  time  and  care  to  it.  The  seams  are 
then  puttied  over  the  calking,  either  with  putty  to  match 
the  rest  of  the  finish  in  color,  or  of  another  color  that  will 
give  a  pleasing  contrast. 

Fig.  7  (b)  shows  method  of  making  a  canvas-covered 
deck.  This  makes  a  very  serviceable  deck,  and  is  easily 
put  on.  Matched  pine  flooring  is  good  stuff  for  the  deck- 
ing, or  waste  material  from  the  planking  may  be  used. 
Xo  partner  piece  or  cut  out  co/ering  boards  are  used. 
Xail  stuff  on  and  then  cut  out  for  coaming  circle,  and 
trim  off  edge  flush  with  sheerstrake.  Paste  canvas  down 
with  a  paste  made  of  rye  flour.  (Stir  up  flour  with  cold 
water  and  cook  till  it  thickens.)  Draw  it  tight  as  pos- 
sible and  tack  over  the  edges  where  fender  strake  and 
coaming  will  hide  the  tacks..  Paint  canvas  with  several 
coats  of  thin  paint.  Green  is  a  good  color. 

Fig.  7  (c  and  d)  shows  stern  decks  of  transom  and 
fantail  boats.  The  coaming  may  be  put  in  either  round 
or  square  to  suit  the  taste  of  the  builder. 

Coaming — Fig.  8  shows  method  of  bending  coaming. 
Strike  a  semicircle  on  the  floor  somewhat  smaller  than 
the  circle  cut  in  the  deck,  to  allow  for  the  coaming 


180 


MOTOR  BOATS: 


springing  out  a  little  after  taking  it  off  the  bending  form. 
Cut  out  some  wood  brackets  and  nail  them  firmly  to  the 
floor  on  this  semicircle.  Bend  the  coaming  around  the 


FIG  8. 

brackets'  as  shown.  When  cool  remove  it  and  screw  it 
into  place,  and  then  dress  it  down  to  the  proper  height. 
Plug  the  screw  heads  for  a  good  appearance.  Use  butt 
blocks  7  to  8  inches  long  to  put  pieces  of  coaming  to- 
gether, and  put  them  on  the  outside  (Fig.  10). 
Interior  Arrangement  and  Finish. 

There  is  ample  choice  of  a  number  of  seating  arrange- 
ments. The  builder  may  suit  himself  in  this  matter, 
though  the  style  with  seats  running  all  around  cockpit 
is  recommended  as  the  best  for  boats  under  22  feet  in 
length,  while  any  of  the  styles  are  suitable  for  larger 
boats. 

Put  in  the  floor  beams  (Fig.  6)  so  that  the  floor  will 
come  about  at  the  bend  of  the  ribs.  To  get  them 
all  level  put  in  a  beam  at  each  end  first  and  be  sure  that 
they  are  at  right  angles  with  the  perpendicular  of  the 
boat,  so  that  the  floor  will  be  level  as  the  boat  sets  in 
the  water.  Also  place  them  at  such  heights  that  the  floor 
will  be  level  fore  and  aft.  Then  stretch  two  lines  con- 
necting the  ends  of  these  beams  and  fit  in  the  remaining 
beams  so  that  they  just  come  up  to  these  lines  at  each 
end.  Then  lay  the  floor  on  these  beams  and  it  will  be 
level. 


CONSTRUCTION  AND  OPERATION 


181 


A  good  interior  finish  is  made  by  ceiling  the  cockpit 
with  narrow  strips  of  ceiling  about  iy2  to  2  inches  in 
width.  This  is  put  in  lengthwise,  starting  at  the  coam- 
ing, and  is  easily  sprung  into  place.  If  you  wish  to  make 
lockefs  under  the  seats  ceil  up  with  the  same  stuff,  run- 
ning the  strips  up  and  down.  -This  when  filled  and  var- 
nished makes  a  very  nice-looking  interior. 


FIG.  9. 

If  you  want  an  extra  fine  job,  panel  the  interior  in  the 
manner  shown  in  Figs.  9  and  10.  Get  your  stuff  out  from 
l/4  inch  to  y$  'inch  thick.  Put  in  the  tuning  pieces,  reach- 
ing from  the  top  of  the  rib  to  the  floor,  of  oak  or  any 
timber  that  will  hold  a  nail  well.  Use  small  brads  and 
countersink  them  with  a  small  nail  set.  Nail  the  panels 
on  first  and  put  the  stiles  on  afterward.  Put  the  length- 
wise stiles  on  first  and  put  in  the  up  and  down  pieces 
afterward.  This  takes  some  careful  fitting  to  make  a 
good  job,,  but  anyone  can  do  it  if  he  is  willing  to  take 
the  time,  and  will  throw  aside  a  piece  if  it  does  not  fit 
and  make  a  new  one.  Paint  the  backs  of  the  panels  be- 
fore putting  them  on.  Panels  of  this  make  are  just  as 
durable  as  the  tongue-and-groove  panel,  and  are  lighter 
and  much  more  easily  made.  Make  the  width  of  the 


182 


MOTOR  BOATS: 


panel  from  2l/2  to  3  times  the  width  of  the  stile,  and 
make  the  panel  from  2  to  3  times  as  long  as  it  is  wide. 
In  paneling  the  side  of  a  cockpit,  for  example,  where  the 
panels  must  be  wider  at  one  end  than  at  the  other,  make 
the  stiles  the  same  width  on  the  whole  job  and  vary  the 


FIG,    10. 

width  of  the  panel  only.  In  paneling  a  cockpit  use  from 
2  to  3  panels  up  the  sides  and  1  or  2  deep  around  the 
lockers.  The  builder  may  have  ideas  of  his  own  for  an 
artistic  arrangement  of  the  panels,  as  there  is  no  set  rule 
to  follow. 

Calking. 

Use  a  small  calking  iron  and  a  mallet.  Calk  the  butts 
first  and  where  plank  joins  stems.  Use  calking  cotton 
if  the  seams  are  uneven,  that  is,  wider  in  some  places 
than  in  others.  Do  not  put  it  in  in  long  straight  strands, 


CONSTRUCTION  AND  OPERATION  183 

but  drive  it  in  in  little  tucks  or  loops  first.  Go  over  about 
a  foot  or  two  of  the  seam  in  this  way  first,  and  then  go 
back  over  it  and  drive  it  in  solid.  Be  sure  to  get  enough 
cotton -in  the  first  time,  as  it  is  a  poor  plan  to  put  more  in 
the  seam  after  it  has  been  once  gone  over.  It  is  apt  to 
work  out  if  you  do.  Fill  the  seam  about  half  full. 

If  the  seams  are  fairly  even  you  can  do  a  much  easier 
and  perhaps  better  job  of  calking  with  a  soft  cotton  cord 
instead  of  the  calking  cotton.  Do  not  tuck  this  in,  but 
run  it  in  straight,  and  drive  it  down  tight  with  a  calking 
iron.  Use  only  a  single  strand.  If  you  have  carelessly 
left  a  seam  too  tight  to  get  the  calking  in,  open  it  up  first 
by  driving  the  calking  iron  along  it. 

When  the  calking  is  done  paint  the  seam  with  thick 
paint,  being  careful  to  touch  all  the  cotton.  This  will 
keep  it  from  coming  out. 

Calk  before  the  boat  is  painted.  After  first  coat  of 
paint,  putty  the  seams  and  nail  heads. 

Engine  Bed  for  DeFoe  Motors. 

Fig.  11  shows  how  to  make  an  engine  bed.  Make 
this  of  oak  from  2  inches  to  4  inches  thick.  Fasten  the 
pieces  together  with  lag  screws. 

The  cross  pieces  must  fit  down  to  the  planking  and  be 
nailed  fast.  Nail  from  the  outside  of  the  boat.  Bolt  the 
cross  piece  through  the  keel.  Put  the 'bolt  head  outside 
and  sink  it  flush  in  the  keel.  Fit  a  block  .between  the 
keel  and  keelson  where  the  bolt  goes  through  so  that 
the  bolt  will  not  bend  them  together.  Fasten  the  motor 
to  the  lengthwise  pieces  with  bolts  or  lag  screws.  Dotted 
line  shows  position  of  motor.  Of  course  this  bed  must 
be  just  the  proper  height  and  pitch  to  bring  your  engine 
in  line  with  the  shaft.  Stretch  a  line  through  the  shaft 
hole  to  the  point  where  the  forward  end  of  engine  shaft 
will  come,  and  make  the  top  of  the  bed  come  level  with 
this  line.  As  DeFoe  motors  have  the  flange  pieces  for 
fastening  to  the  bed  on  a  line  with  center  line  of  the 


184 


MOTOR  BOATS: 


shaft,  the  engine  will  then  be  in  line  when  it  is  placed 
on  the  bed.  As  the  line  must  be  taken  down  before  the 
engine  is  placed,  mark  the  points,  by  nailing  pieces 
(marked  X,  Fig.  11)  up  to  the  line  from  the  keelson 
where  each  end  of  the  engine  shaft  should  come  in  order 


•ntcr  Of  forwd  en& 

B-n^tne 


rear  end, 


FIG.  11. 

to  be  in  exact  line  with  the  stern  bearing.  Of  course 
the  engine  shaft  should  lie  exactly  where  the  line  was. 
This  will  bring  it  if  you  are  careful.  Measure  the  engine 
shaft  and  get  the  two  points  just  this  distance  apart. 
The  lag  screws  that  fasten  the  fore  and  aft  pieces  to  the 
forward  cross  piece  will  in  most  cases  fasten  the  engine 
down  also.  The  dotted  line  shows  the  position  of  the 
engine  on  the  bed. 


CONSTRUCTION  AXD  OPERATIOX  185 

Steering  Gear. 

Figs.  3  (a)  and  3  (b)  show  two  methods  of  putting  on 
the  rudder.  Use  a  piece  of  gas  pipe  for  the  port,  thread  it 
on  one  end  and  screw  it  into  the  wood.  Make  the  rudder 
of  common  sheet  steel  about  ^  inch  thick,  and  make 
the  rudder  post  and  lower  bearing  of  round  iron  about 
•;.;'  inch  in  diameter  in  smaller  boats  to  1^4  inches  in 
larger  ones.  Square  the  upper  end  of  rudder  post  to  fit 
the  tiller.  Split  the  lower  end  to  straddle  the  rudder, 
and  rivet  it  on  securely.  Attach  the  lower  bearing,  Fig. 
3  (a),  in  the  same  way,  where  a  shoe  is  used,  and  make 
the  shoe  of  iron.  Turn  the  end  of  the  shoe  over  as  shown 
and  put  a  key  in  the  end  of  the  bearing  to  keep  rudder 
from  jumping  out. 

The  stuffing-box  may  be  put  either  inside  or  outside — 
better  outside  on  small  boats  at  least,  as  it  needs  no 
Moreover,  if  it  is  properly  packed  it  will  not  need  further 
lubrication  there,  and  if  it  should  need  repacking  *it 
would  be  no  great  task  to  raise  the  boat  up  to  reach  it. 
attention  for  a  season  at  least. 

Use  cotton  sash  cord  to  connect  tiller  with  steering 
wheel.  The  best  arrangement  is  to  keep  the  tiller  below 
the  deck,  and  run  the  cords  around  just  below  the  coam- 
ing on  each  side  to  the  steering  wheel.  Use  blocks  at  the 
four  corners  where  there  is  a  quick  turn,  and  small  screw 
eyes  under  the  coaming.  Some  prefer  to  have  the  tiller 
and  ropes  above  the  deck.  In  this  case  use  four  small 
cheek  blocks  and  small  brass  eyelets  to  carry  the  cord. 
It  will  be  necessary  to  bore  holes  in  the  coaming  forward 
to  get  the  ropes  to  the  steering  wheel  if  they  are  put 
above  deck. 

Steam  Box. 

Fig.  12  shows  a  very  simple  and  yet  very  effective 
steam  box.  Use  a  common  laundry  room  boiler,  or  a 
good  sized  kettle  or  pail  will  do  for  a  small  box:  Make 


186 


MOTOR  BOATS: 


the  box  of  %  inch  boards.  Nail  it  solidly  and  make  the 
joints  very  tight  to  hold  the  steam.  Leave  the  ends 
open.  A  seven-foot  box  that  will  take  a  12  inch  board  is 
large  enough  for  most  purposes.  Cut  a  cover  for  the 
boiler  from  a  %  inch  board  and  make  it  just  large 
enough  to  slip  into  the  boiler  and  fit  snug.  Nail  the 
cover  to  the  bottom  of  the  box.  Put  two  or  three  inches 
of  water  in  the  boiler  and  set  the  whole  thing  on  the 
stove.  If  you  have  no  stove  handy  set  it  over  a  fire 
built  out  of  doors.  Get  it  as  hot  as  possible. 


Cozier. 


FIG.  12. 

Put  the  material  to  be  steamed  in  the  box  and  plug 
up  the  ends  tightly  with  rags.  If  you  are  steaming  a 
long  piece,  such  as  a  coaming,  let  the  ends  stick  out  of 
the  box  and  pack  around  them  with  rags  to  keep  the 
steam  in.  The  amateur  may  work  out  a  scheme  of  his 
own  that  will  answer  equally  well ;  but  this  box,  though 
crude  in  appearance,  will  answer  all  purposes. 

By  far  the  best  way  to  treat  the  ribs  for  bending  is 
to  procure  a  metal  trough  that  is  long  enough  to  hold 
them,  and  boil  them  in  it  for  a  half  hour  or  so.  Put  a 
cover  on  the  trough  and  boil  them  hard,  and  they  can 
be  made  very  pliable.  The  steam  box  will  answer,  how- 
ever, unless  ribs  are  of  poor  stuff. 

Shop,  Tools,  Etc. 

If  you  have  a  shop  and  a  full  set  of  tools,  so  much 
the  better,  though  the  ordinary  tools  to  be  found  in  most 


CONSTRUCTION  AND   OPERATION  187 

every  household  with  very  few  additions  will  be  suf- 
ficient. A  hammer,  handsaw,  ripsaw,  screwdriver,  jack- 
plane,  smooth  plane,  a  chisel  or  two,  a  brace  and  a  few 
sizes  of  bits,  about  a  half  dozen  clamps  from  4  inches  to  , 
8  inches  and  a  draw-knife.  If  you  haven't  all  of  them 
borrow  them  of  your  neighbor  and  give  him  a  ride  in 
the  boat  when  it  is  finished.  Keep  your  tools  sharp. 

A  light,  warm  shop  is  of  course  the  most  desirable 
place  in  which  to  build  your  boat.  But  if  you  haven't 
such,  fit  up  the  basement,  the  woodshed,  or  the  barn. 
Put  a  bench  along  one  side  about  14  feet  long.  Use 
planks  for  the  top,  and  it  should  be  about  the  height  of 
the  builder's  hip  joint.  Have  a  vise  at  the  left  hand  end. 
Of  course  the  more  convenient  the  shop,  and  the  better 
the  tools,  the  more  pleasant  will  be  the  work,  and  natur- 
ally the  better  will  "be  the  results. 

Painting,  Varnishing  and  Finishing. 

Use  white  lead  and  oil  mixed  very  thin  for  a  priming 
coat  of  paint.  Next  putty  all  nail  heads  and  seams..  A 
good  boat  putty  is  made  by  mixing  whitening  with 
white  lead,  (not  the  dry  lead,  but  the  ordinary  kind 
which  is  ground  in  oil)  until  it  is  the  proper  consistency. 
Add  about  a  teaspoon  of  Japan  dryer  to  every  pound  of 
it  before  mixing.  A  quick  drying  and  very  durable 
putty  is  made  by  mixing  equal  parts  by  bulk  of  whiten- 
ing and  dry  white  lead  with  varnish.  Any  varnish  will 
do;  some  old  stuff,  perhaps,  that  you  may  have  around 
the  house.  This  putty  is  sticky  and  hard  to  apply 
smooth,  but  will  dry  hard  in  three  or  four  days.  Sand 
the  hull  down  perfectly  after  puttying,  and  apply  at 
least  two  or  more  coats,  sanding  between  coats.  Be  sure 
that  each  coat  is  thoroughly  dry  before  you  apply  the 
succeeding  one. 

For  a  varnished  finish  proceed  as  follows:  All  screw 
heads,  bolt  heads,  and  the  like,  should  be  plugged  with 
wood  plugs.  These  plugs  can  be  purchased  at  most 


188  MOTOR  BOATS: 

hardware  stores,  or  you  can  purchase  a  plug  cutter,  a 
cheap  tool,  and  cut  them  yourself.  They  should  be  of 
the  same  wood  as  the  remainder  of  your  work  and  should 
be  put  in  so  that  the  grain  runs  in  the  same  direction. 
Dip  them  in  shellac  and  drive  them  into  the  hole  and  they 
will  stay.  When  dry  dress  them  off  with  a  plane  or  a 
chisel.  Then  scrape  and.  sandpaper  the  wood  to  a  perfect 
surface,  as  any  little  blemish  will  show  up  badly  after 
the  finish  is  on. 

Next  apply  the  filler.  If  you  are  building  only  one 
boat,  it  will  be  better  to  use  prepared  stains  and  fillers ; 
and  if  you  tell  your  dealer  what  results  you  want,  light 
oak  finish,  dark  oak,  mahogany,  cherry,  or  whatever  it 
may  be,  he  will  furnish  you  with  the  proper  materials. 
The  boat  and  frame  builders  also  carry  these  things  in 
stock  and  will  make  immediate  shipment  if  you  order 
from  them.  Directions  will  usually  be  found  on  the 
package  for  applying  the  filler.  A  rub  filler  is  recom- 
mended as  giving  the  best  results,  and  a  water  stain. 
There  are  many  good  fillers,  but  be  careful  if  you  use  a 
stain,  for  they  are  apt  to  raise  the  grain  of  your  wood  or 
fade  out  in  time  unless  they  are  exactly  what  they  ought 
to  be. 

Sand  the  filler  with  fine  sand  paper,  putty  all  nail 
heads,  seams,  etc.,  and  when  dry  apply  a  coat  of  spar 
varnish,  (get  the  best  putty  and  use  no  other  varnish 
than  spar)  and  sand  carefully,  rubbing  lengthwise  of 
the  grain  only.  Follow  with  a  second  coat  in  the  same 
way,  and  finish  with  the  third  coat.  Three  coats  of  any 
good  spar  varnish  are  sufficient.  Let  the  filler  and  .each 
coat  of  varnish  dry  thoroughly  before  the  succeeding  coat 
is  put  on.  Otherwise  it  will  check  and  may  peel. 

An  excellent  rub  filler  is  made  by  mixing  equal  parts 
of  whitening  and  cornstarch  and  adding  turpentine  un- 
til it  becomes  the  consistency  of  paste.  This  will  give  a 
colorless  filler  and  when  applied  will  leave  the  wood  its 


CONSTRUCT/OX  AXD   OPERATION  .  189 

natural  color  and  appearance.  However,  fillers  are  gen- 
erally colored.  In  using  a  coloring  matter,  either  dry  or 
in  oil,  always  dissolve  it  in  turpentine  before  adding  it 
to  your  filler  or  paint. 

There  are  a  variety  of  shades  of  finish  for  golden  oak, 
mahogany,  cherry,  etc.,  and  the  best  way  to  proceed  is  to 
purchase  a  few  dry  colors  of  brown,  pink  and  red,  and  a 
little  experimenting  will  produce  a  color  that  will  suit 
your  individual  taste. 

To  apply  the  filler  thin  it  with  turpentine  (use  also 
about  4  teaspoonfuls  of  paint  oil  and  a  spoonful  of 
Japan  dryer  to  a  quart  of  turpentine),  and  apply  it 
with  a  brush,  like  paint,  putting  it  on  about  as  thick  as 
paint.  In  from  one  to  five  minutes  you  will  notice  that 
dry  spots  will  begin  to  show  in  the  filler.  Then  take  a 
handful  of  waste  or  an  old  cloth  and  rub  off  all  the  sur- 
plus filler,  rubbing  always  across  the  grain  of  the  wood 
in  order  to  fill  the  pores.  Finally  use  a  clean  cloth  and 
rub  off  all  the  filler  that  will  come  off.  The  filler  should 
then  dry  about  12  hours  before  the  varnish  is  applied. 

If  you  want  a  decided  color,  such  as  a  very  dark  oak 
or  a  dark  mahogany,  use  a  stain  first.  You  can  make 
this  yourself  by  simply  mixing  your  dry  powders  with 
water  and  applying  them  to  the  wood  with  a  cloth. 
Care  must  be  taken  not  to  leave  the  wood  looking 
streaked.  Apply  the  filler  after  the  stain  is  on. 

Useful  Hints. 

Nail  planking  on  with  clout  nails.  Bore  through  or 
nearly  through  the  part  to  be  fastened,  and  have  the 
nail  long  enough  to  reach  away  through  and  clinch  over 
about  y$  or  %.  of  an  inch.  Hold  an  iron  against  the 
spot  and  nail  through  against  it  to  clinch  or  double  the 
point  of  the  nail  over. 

Always  bore  for  a  nail  where  there  is  any  likelihood 
of  splitting.  Bore  the  hole  about  two-thirds  the  size  of 
the  nail. 


190  MOTOR  BOATS: 

Always  bore  for  a  screw  full  depth,  with  a  bit  slightly 
smaller  than  the  screw,  and  countersink  for  the  head  of 
the  screw. 

White  oak  bends  with  steaming  better  than  any  other 
timber.  For  this  reason  it  is  often  used  for  garboards 
(the  plank  next  to  keel)  that  are  difficult  to  put  on.  For 
this  reason  also,  and  by  reason  of  its  toughness  and 
durability,  it  is  used  almost  entirely  for  frames.  Dry 
timber  bends  better  with  steaming  than  wet  timber. 

Clamp  the  whole  sheerstrake  on  before  you  fasten  any 
part  except  to  the  stem  and  stern.  You  can  better  line 
it  up  in  this  way. 

In  using  a  bolt  always  put  a  washer  under  the  nut. 

Special   Building   Instructions   for  an    18-foot   Standard 
Stern  Launch. 

In  setting  up  the  frame,  keel  sh'ould  run  straight  from 
stem  to  fore  end  of  skeg.  Then  raise  the  aft  end  of  keel 
3y2  in.  above  this  straight  line.  Do  not  let  the  keel 
curve  down  between  the  stem  and  skeg.  (See  Fig.  1, 
General  Instructions  above.) 

Lumber — See  General  Instructions  for  the  kind  of 
lumber  to  use  for  the  different  purposes,  such  as  plank- 
ing, ribs,  decks,  etc.  Purchase  as  follows :  For  plank- 
ing, 200'  of  */>"  stuff  (may  use  y%"  if  you  desire).  For 
keel,  one  piece,  Ij^"x5",  10'  long,  and  1  piece  I^"x5", 
8'  long,  or,  instead  of  the  two  pieces,  1  piece  18'  long. 
For  keelson,  1  piece  17'  long,  or  2  pieces  same  as  keel. 
For  ribs  get  250  running  feet  of  white  oak,  ^"x^/s",  or 
get  25'  of  T/%"  stuff  and  rip  out  ribs  by  hand.  Space 
them  8"  apart.  For  clamps,  2  pieces,  %"xl%",  14' 
long,  run  at  top  of  sheerstrake  and  only  from  deck  to 
deck.  For  transom,  1  piece  %"x21^2",  3'  long;  or  1 
piece  %"xll",  6  long.  For  stem,  stern  post,  skeg,  etc., 
1  piece  %"xlO",  12'  long.  For  fenders,  38'  of  J^"  half 


CONSTRUCTION  AND  OPERATION  191 

round.  For  coaming,  2  pieces  ^"x$",  12'  long,  and  one 
piece  3'  long.  For  covering  boards,  2  pieces  y%"j&",  10' 
long.  For  flooring,  60'  of  */2X/  stuff-.  If  you  wish  to  use 
a  different  wood  for  sheerstrake,  get  2  pieces  £/s"x7",  9' 
long,  and  2  pieces  ^"x7",  12'  long. 

See  General  Instructions  for  interior  finish. 

Make  forward  deck  about  4'  long;  aft  deck  about  2l/2'. 
Space  deck  beams  same  as  ribs,  8"  apart. 

Hardware — 6  Ibs.  \l/>"  clouts,  for  planking.  1  Ib.  four- 
penny  wire  nails  to  nail  plank  to  stem.  Use  */J"  bolts  in 
stem  and  keel;  40  bolts,  y4"*2y4"  for  clamps.  Six 
'4  "x2"  bolts  for  splice  in  clamp.  One  hundred  \V4"  No. 
12  screws  for  sheerstrake. 

Some  small  items  will  be  needed  in  addition  and 
should  be  purchased  as  the  work  progresses. 


"Going  Some." 


CHAPTER  XVII 
PROPELLERS. 

The  propeller  is  one  of  the  most  important  parts  of 
the  boat  and  is  generally  the  least  understood  even  in 
its  most  elementary  principles.  An  improperly  designed 
or  selected  propeller  for  a  given  hull  will  cause  a  loss  of 
power,  fuel  and  speed,  and  many  of  the  troubles  that 
are  commonly  charged  to  the  account  of  the  engine  can 
be  traced  directly  to  an  incorrect  wheel.  The  selection 
of  a  wheel  depends  on  the  engine  speed,  boat  speed,  duty 
for  which  boat  is  intended,  water  in  which  it  is  to  be 
used,  and  the  local  conditions  governed  by  the  wheel 
location  and  the  form  of  the  hull.  In  buying  a  propeller 
it  is  by  far  the  best  method  to  consult  a  responsible  pro- 
peller maker  and  acquaint  him  with  all  of  the  conditions 
under  which  the  proposed  wheel  is  to  work. 

In  default  of  such  information  the  owner  will  be  con- 
fronted by  two  of  the  first  terms  used  in  specifying  a 
propeller,  that  is,  diameter  and  pitch.  The  diameter, 
which  is  the  distance  from  tip  to  tip  of  opposite  blades 
measured  across  the  center  of  the  shaft  bore,  is  easily 
measured.  The  pitch,  however,  is  a  term  not  so  easily 
understood  and  therefore  is  a  matter  that  must  be 
described  more  in  detail. 

In  certain  respects  a  propeller  may  be  compared  with 
a  machine  screw  working  in  a  nut.  Every  revolution  that 
the  screw  is  turned  it  advances  a  certain  distance  in  the 
direction  of  its  length.  The  distance  traveled  per  revolu- 
tion is  called  the  "pitch"  of  the  screw.  In  the  same  way 
a  propeller  screws  its  way  through  the  water,  the  pro- 
peller blades  acting  in  the  same  way  as  the  threads  on 


CONSTRUCTION  AND  OPERATION  193 

the  screw.  The  difference  between  the  two  lies  in  the 
fact  that  the  water  is  not  a  solid  rigid  substance  like  the 
nut  on  the  screw  and  therefore  the  propeller  slips  or  fails 
to  advance  by  the  amount  of  the  theoretical  pitch.  The 
difference  between  the  theoretical  advance  of  the  wheel 
and  the  actual  advance  is  known  as  the  "slip"  and  is 
usually  given  in  terms  of  the  theoretical  pitch.  The  slip 
sometimes  amounts  to  as  much  as  50  per  cent  of  the  the- 
oretical pitch,  or  50  per  cent  of  the  distance  that  the  boat 
should  move  through  the  water  for  every  revolution  of 
the  wheel  were  there  no  slippage.  The  speed  that  a  boat 
would  make  were  there  no  slippage  is  called  the  theo- 
retical speed. 

The  slope  of  the  blade  with  the  line  of  the  shaft  is 
usually  an  index  to  the  pitch,  that  is,  the  greater  the 
blade  angle,  the  greater  the  pitch.  Measurement  of  the 
pitch  by  means  of  the  blade  angle  is  not  so  simple  a 
manner  as  would  be  thought  at  first  glance,  since  on  close 
examination  it  will  be  noted  that  the  angle  rapidly  in- 
creases from  the  tip  to  the  hub.  Take  a  45  degree  tri- 
angle and  slide  it  along  the  working  face  of  the  blade 
until  one  edge  of  the  triangle  is  parallel  to  the  shaft  line 
in  hub.  This  is  the  45  degree  point  on  the  blade  and  will 
be  approximately  half  way  between  the  tip  of  the  blade 
and  the  hub,  and  generally  at  the  widest  part.  At  this 
point  the  pitch  will  be  the  same  as  the  length  of  the  cir- 
cumference of  the  imaginary  circle  that  passes  through 
this  point.  Rule.  Measure  the  distance  from  the  45 
degree  point  on  the  blade  to  the  center  of  the  shaft  hole 
and  multiply  this  dimension  by  6.28.  This  will  give  the 
theoretical  pitch. 

Example — The  distance  from  the  45  degree  point  to 
the  center  of  the  shaft  was  found  to  be  14^  inches.  Find 
the  pitch.  14.5  X  6.28  =  91  inches  =  7.58  feet,  the  the- 
oretical pitch. 

The  theoretical  speed  of  the  boat  in  feet,  with  no  slip, 


194  MOTOR  BOATS: 

can  be  found  by  multiplying  the  speed  of  the  engine  by 
the  pitch  as  found  above.  Taking  the  pitch  as  found 
above  and  an  engine  speed  of  600  revolutions  per  minute 
the  theoretical  speed  will  be,  600  X  7-58  —  4548  feet  per 
minute.  Since  there  are  5280  feet  per  mile,  4548  -r-  5280 
=  0.86  miles  per  minute,  or  60  X  0.86  =  51.6  miles  per 
hour. 

Stated  in  a  simpler  form,  this  will  be 
PN       7.58  X  600 

= =  51.6  miles  per  hour,  where  P  =  pitch 

88  88 

in  feet,  N  =  number  revolutions  per  minute,  and  88  is  a 

5280   . 
factor  derived  from  -    —  —  88.    Assuming  a  slip  of  50  per 

60 

cent,  the  true  or  actual  speed  will  be  51.6  X  0.50  =  25.8 
miles  per  hour.     Inserting  the  slip  or  efficiency,  E,  into 
the  above  formula  we  have  the  actual  speed  of 
PN        7.58X600 

— =  25.8  miles  per  hour. 

88  E        88  X  0.50 

It  must  be  understood  that  the  efficiency  of  50  per  cent 
does  not  apply  to  all  cases  and  was  only  chosen  for  the 
sake  of  having  a  concrete  example. 

The  ratio  of  the  pitch  to  the  diameter  of  a  propeller 
is  called  its  "Pitch  Ratio,"  and  this  ratio  varies  in  pro- 
pellers designed  for  different  classes  of  service.  A  high 
speed  boat  requires  a  higher  pitch  ratio  than  a  slow  speed 
boat  for  heavy  duty  such  as  a  tug  or  work  boat. 

The  diameter  of  a  wheel  is  of  the  greatest  importance 
since  the  thrust  of  the  wheel  is  concentrated  on  the  face 
of  the  blades  or  rather  the  disc  area  (diameter  squared 
X  0.7854)  and  as  this  must  not  exceed  a  certain  amount 
in  pounds  per  square  foot  to  prevent  breaking  through 
the  water  we  must  have  ample  area.  In  general,  it  is 
desirable  to  have  as  large  a  wheel  as  can  be  swung  for 


CONSTRUCTION  AND  OPERATION  195 

another  reason,  that  is,  a  large  wheel  is  more  efficient  in 
the  utilization  of  power. 

The  pressure  per  square  foot  on  the  surface  of  the  blades 
should  not  exceed  400  pounds.  If  this  pressure  is  ex- 
ceeded the  slip  stream  of  the  propeller  will  be  broken 
and  "cavitation"  or  holes  produced  which  will  reduce 
the  thrust  or  push  and  increase  the  power.  Dividing 
the  total  thrust  by  400  will  give  the  area  of  the  blades 
(area  of  all  blades)  in  square  feet.  The  value  of  the 
thrust  at  the  given  boat  speed  may  be  had  from  the  builder 
of  the  boat,  or  may  be  found  experimentally  by  towing 
the  loaded  hull  behind  another  boat  at  the  given  speed,* 
the  thrust  being  measured  by  a  spring  balance  or  ice 
scale  attached  to  the  tow  rope.  Care  should  be  taken  in 
making  this  test  to  place  a  weight  in  the  hull  equal  to 
that  of  the  combined  weight  of  the  engine,  fuel  and  crew. 
Always  tow  at  the  highest  speed  that  you  intend  to  make, 
against  the  wind,  current  and  with  everything  adjusted 
in  its  normal  position.  When  the  boat  is  to  be  used  in 
shallow  or  rough  water,  the  factor  400  should  be  reduced 
to  250  to  300.  When  thrust  is  determined  divide  by 
above  factor  thus  obtaining  total  blade  area. 

Knowing  the  thrust,  area  of  propeller,  and  boat  speed 
we  can  obtain  the  approximate  slip  from  the  formula 

TV 
S  =  -     -  where  S  is  the  slip  in  feet  per  second ;  T  is  the 

Av 

thrust  in  pounds,  V  is  the  boat  speed  in  feet  per  second ; 
A  is  the  area  of  propeller  disc  (.7854  X  diameter  squared) 
in  feet,  and  v  is  the  velocity  of  slip  stream  relative  to  boat 
speed.  The  total  slip  S  is  added  to  the  boat  speed  to 
obtain  the  theoretical  velocity  of  the  propeller.  When 
reduced  to  feet  per  minute  and  divided  by  the  engine 
revolutions,  the  result  will  be  the  theoretical  pitch  given 
the  propeller. 

While  the  propeller  should  be  as  large  as  possible  it 


196.  MOTOR  BOATS: 

should  not  break  through  the  surface  of  the  water  nor 
be  below  the  skeg  so  as  to  run  chances  of  striking  rocks 
or  lying  in  the  mud.  A  good  propeller  has  only  a  slip 
of  from  20  to  30  per  cent. 

In  regard  to  the  number  of  blades  in  the  wheel  there 
is  a  certain  diversity  of  opinion.  In  work  boats  and  large 
cruisers  in  which  the  wheels  should  be  as  large  as  pos- 
sible the  engine  can  turn  a  larger  two  blade  than  three 
blade,  thus  placing  the  results  in  favor  of  the  two  blade 
wheel.  For  the  same  reason  small  boats  generally  have 
two  bladed  wheels  since  it  is  possible  to  have  them 
larger  and  therefore  act  on  larger  bodies  of  water.  This 
reduces  the  churning.  Where  the  thrust  per  square  foot 
of  blade  area  must  be  high  owing  to  limitations  placed  on 
the  diameter  by  the  construction  of  the  boat  three  blades 
will  generally  be  found  necessary.  On  large  boats  with 
very  heavy  thrusts,  slow  speeds,  and  small  head  room, 
four  blades  will  often  be  found  necessary. 

In  boats  where  the  dead  wood  is  very  thick  and  acts 
as  a  shield  to  the  wheel,  three  blades  will  act  better  than 
two  as  there  will  always  be  two  blades  active  while  the 
third  is  in  the  shadow  of  the  dead  wood.  The  propeller 
should  be  placed  a  sufficient  distance  from  the  stern  post, 
rudder  and  other  parts  of  the  boat  to  insure  easy  access 
of  water  to  the  wheel.  The  stern  post  should  be  tapered 
and  as  narrow  as  possible  to  prevent  the  effects  of  shield- 
ing. Boats  with  wide  bluff  sterns  should  have  wheels 
with  small  throats  and  large  balloon  ends  because  the 
stream  does  not  turn  into  the  center  of  the  wheel. 

It  should  be  remembered  in  this  regard  that  the  fric- 
tion of  the  hull  in  the  water  causes  the  water  to  follow 
the  hull  at  a  certain  speed  (following  wake)  so  that  the 
propeller  acts  on  water  that  is  moving  at  about  half 
the  boat  speed  and  in  the  same  direction.  For  this  rea- 
son the  propeller  at  the  back  is  more  effective  in  produc- 
ing speed  than  one  at  the  bow*  pitches  being  equal  in 


CONSTRUCTION  AND  OPERATION  197 

both  cases.  With,  the  wheel  at  the  rear  the  actual  boat 
speed  is  equal  to  the  actual  propeller  speed  in  open  water 
plus  the  velocity  of  the  frictional  wake. 

The  blades  for  normal  service  should  be  elliptical  in 
shape,  the  width  of  the  blade  being  about  0.4  of  the 
length,  the  width  being  the  minor  axis  of  the  ellipse. 

High  speed  boats  require  clover  leaf  wheels  with  al- 
most circular  blades,  usually  three  in  number  and  so  wide 
that  the  edges  almost  overlap.  The  widest  point  of  a 
blade  for  normal  service  should  be  at  the  45  degree  point 
while  with  high  speed  blades  this  greatest  width  conies 
nearly  to  the  root  of  the  blades.  For  average  high  speed 
the  blades  should  flare  out  from  the  root  to  the  center 
and  should  never  taper  from  root  to  tip. 

Thrust  Bearings. 

When  at  work,  the  thrust  of  the  propeller  tends  to 
force  the  propeller  shaft  toward  the  hull  or  in  a  direction 
opposite  to  the  thrust  of  the  blades  when  the  boat  is 
moving  forward.  W^hen  the  boat  is  moving  astern  the 
direction  of  the  pressure  is  also  reversed.  It  is  custo- 
mary for  the  engine  builder  to  build  a  special  thrust 
bearing  into  the  engine  for  taking  up  this  axial  force, 
which  is  by  no  means  of  small  degree. 

In  the  smaller  motors  the  thrust  bearing  is  of  the  ball 
or  roller  type,  one  race  being  imbedded  in  the  engine 
frame  while  the  other  race  is  fastened  to  the  shaft  in 
such  a  way  that  steel  balls  or  rollers  fill  the  space  be- 
tween the  two  races.  Two  independent  sets  of  thrust 
bearings  are  provided  by  some  builders,  one  set  taking 
the  thrust  from  the  forwar^  drive  while  the  second  set 
takes  the  thrust  from  the  reverse. 

Right  and  Left  Hand  Propellers. 

As  a  propeller  blade  has  only  one  efficient  driving  face 
and  for  the  reason  that  this  limits  the  direction  in  which 


198  MOTOR  BOATS: 

the  wheel  may  rotate  when  driving  full  ahead,  it  is  neces- 
sary to  give  the  direction  of  engine  rotation  in  ordering 
the  propeller.  This  often  leads  to  misunderstanding  and 
mistakes  in  delivery  for  the  reason  that  the  customer 
seldom  knows  in  which  direction  to  face  the  engine  when 
taking  the  rotation,  nor  in  fact,  how  to  read  the  direction 
at  all.  For  the  benefit  of  those  who  have  not  had  this 
experience  we  will  illustrate  and  describe  what  is  prac- 
tically a  standard  method  among  engine  and  propeller 
makers. 

Standing  in  front  of  the  engine,  and  facing  the  fly- 
wheel, look  aft  while  the  engine  is  running.  If  the  top 
of  the  fly-wheel  turns  from  the  right  to  the  left  a  right 
hand  wheel  is  needed.  If  it  turns  from  the  left  to  right, 
a  left  hand  wheel  is  needed.  A  left  hand  engine  needs 
a  right  hand  propeller,  if  rotation  is  viewed  while  looking, 
aft. 

Construction  of  Propellers. 

In  the  practical  propeller  there  are  a  number  of  differ- 
ences from  the  true  screw  propeller  just  mentioned,  the 


>--' 


FIG.  1. — Graphical  Representation  of  Pitch  and  Blade  Angle. 

differences  depending  principally  on  the  service  to  which 
the  blade  is  to  be  put,  the  speed  at  which  it  rotates,  etc. 
In  some,  the  angle  of  the  blade  is  constant  from  tip  to 
root  (constant  angle  propeller),  in  others  the  blade 


CONSTRUCTION  AND  OPERATION  199 

angle  increases  from  tip  to  root  (uniform  pitch), 
and  in  some  cases  the  blade  angle  varies  ac- 
cording to  the  addition  of  some  constant  angle  to 
the  angle  of  the  uniform  pitch  system.  Constant  angle 
propellers  are  as  a  rule  not  efficient  for  the  reason  that 
the  inner  portions  of  the  blade  drag  in  the  water  and 
therefore  do  not  exert  a  propulsive  force  throughout  the 
greater  part  of  their  length.  That  this  is  true  will  be 
proved  by  the  following  description  of  the  true  screw  or 
uniform  pitch  propeller. 

A  simple  propeller  is  shown  by  Fig.  1  in  which  the 
path,  blade  angle  and  pitch  are  shown  in  their  relative 
positions.  In  the  upper  right  hand  corner  is  shown  the 
cylinder  diameter  swept  by  the  blades,  the  height  of  the 
cylinder  being  equal  to  the  pitch,  or  to  the  distance 
traveled  by  the  boat  in  one  revolution.  In  traveling  this 
distance,  it  is  evident  that  a  point  on  the  tip  of  the  blade 
will  not  only  revolve  about  the  center  but  will  also 
advance  forward  by  a  distance  equal  to  the  pitch.  This 
results  in  the  tip  of  the  blade  actually  traveling  along 
the  inclined  curve,  the  latter  being  known  as  a  "helix." 
In  other  words,  the  blade  climbs  up  an  inclined  plane. 

Say,  for  example,  that  the  cylinder  of  revolution  is  cut 
along  the  pitch  dimension  and  straightened  out  as  shown 
in  the  figure  in  the  lower  left  hand  corner  giving  an  in- 
clined plane  or  wedge  in  which  the  height  is  the  pitch 
and  the  base  length  is  equal  to  the  length  of  the  circle 
formerly  described  by  the  tips  of  the  blade.  The  hy- 
potenuse, or  inclined  line  of  the  triangle  is  the  exact  path 
followed  by  the  tip  of  the  blade,  while  the  angle  between 
the  base  and  the  hypotenuse  is  the  blade  angle.  Actually 
the  angle  of  the  blade  is  slightly  greater  than  the  pitch 
angle  to  allow  for  slip.  Thus  by  knowing  the  pitch  re- 
quired and  the  circumference  of  the  circle  swept  by  tips 
it  is  possible  to  construct  the  theoretical  blade  angle  by 
the  means  shown. 


200  MOTOR  BOATS: 

As  shown,  this  blade  would  have  a  constant  angle  from 
tip  to  root  which  would  not  fulfil  the  conditions  since 
the  inner  portions  would  drag  on  the  outer.  That  this 
is  true  can  be  proved  by  drawing  a  series  of  triangles 
taken  at  different  points  in  the  blade  length,  the  base  of 
the  triangle  being  taken  as  equal  to  the  circumference 
of  the  circle  passing  through  the  blade  at  that  point 
while  the  height  or  pitch  is  kept  constant  in  all  triangles. 
The  latter  condition  is  necessary  for  the  reason  that  all 
parts  of  the  blade  must  travel  forward  a  distance  equal 
to  the  pitch  in  one  revolution.  When  these  triangles 
are  drawn  it  will  be  seen  that  the  blade  angle  is  differ- 
ent in  each  one,  the  angles  increasing  as  the  root  of  the 
blade  is  approached.  With  a  constant  angle  the  root 
portions  of  the  blade  would  not  pass  the  water  fast 
enough  to  correspond  with  the  water  displaced  with  the 
tips.  At  the  center  of  the  hub,  the  blade  would  be  at 
exactly  right  angles  to  the  center  of  the  shaft. 

Fig.  2  (Diag.  A)  shows  this  construction  more  in  de- 
tail, ABCD  being  known  as  the  "pitch"  or  ''displace- 
ment" cylinder.  The  diameter  D1  of  the  cylinder  is  made 
equal  to  the  propeller  diameter  while  the  pitch  is  shown 
by  P,  and  the  propeller  blade  by  Z.  In  progressing  from 
X  to  X  along  the  cylinder  center  line,  a  point  on  the  tip 
of  the  blade  Z  traces  a  "flight"  curve,  or  helix,  XFYEX 
in  which  the  direction  of  progress  is  indicated  by  the 
small  arrow  heads  on  the  curve.  The  progress  of  the 
propeller  is  indicated  by  the  arrow  W,  that  is,  the  whole 
propeller  moves  from  right  to  left.  In  passing  from  F  to 
E,  a  distance  equal  to  the  pitch,  the  propeller  has  made 
one  complete  revolution  along  the  curve  FYE.  A  front 
elevation  of  the  propeller  is  shown  by  Diag.  B  in  which  M 
and  N  are  the  blade  tips,  O  is  the  shaft,  Q  is  the  hub, 
and  S-T  is  the  circle  described  by  the  tips,  equal  to  the 
cylinder  diameter  D.1 

Suppose  that  we  wish  to  find  the  blade  angle  condi- 


CONSTRUCTION  AND  OPERATION     . 


201 


202  MOTOR  BOATS: 

tioris  existing  at  the  points  I  and  L  on  the  blade  MN, 
the  points  being  assumed  to  lie  on  the  circle  R-R,  in 
Diag.  B,  and  on  the  blade  at  G  in  Diag.  A.  The  diameter 
of  this  auxiliary  circle  will  be  indicated  by  d,  and  its  path 
cylinder  is  shown  in  Diag.  A  by  the  outline  JJ1KK,1  the 
cylinder  being  shaded  to  distinguish  it  from  the  sur- 
rounding lines. 

As  in  the  case  of  the  blade  tip  cylinder,  a  second  helix 
HMG  is  drawn  for  the  inner  circle  path.  This  curve 
starts  and  ends  on  the  same  vertical  lines  as  the  first 
curve  since  the  pitch  distances  GH  and  EF  must  be 
equal  to  one  another  and  also  to  the  pitch  P.  With  the 
second  HMG  curve  drawn  on  the  smaller  diameter  d  it 
will  be  noted,  for  equal  pitches,  that  the  angle  with  the 
vertical  is  considerably  greater  than  the  angle  of  the 
helix  FYE.  These  angles  are  indicated  by  b  and  a,  the 
first  being  the  angle  of  curve  FYE.  An  outline  of  the 
blade  section  at  the  tip  is  shown  by  the  solid  black  sec- 
tion 2-2,1  while  the  blade  section  at  the  points  I  and  L 
on  the  propeller  is  shown  by  the  dotted  outline  3-3.1  In 
this  view  we  are  supposed  to  be  looking  at  the  ends  of 
the  blade,  and  proves  conclusively  that,  for  uniform,  or 
equal  pitches  we  must  increase  the  angle  as  we  approach 
the  root  or  hub  Q.  Performing  the  same  operation  with  a 
circle  drawn  through  the  point  V  we  will  find  that  the 
blade  angle  is  greater  than  at  the  tip,  but  less  than  at 
the  point  I.  The  variation  is  indicated  by  the  shade 
lines- in  Diag.  B. 

Unfortunately  the  actual  design  is  not  as  simple  as 
this  for  very  efficient  results,  owing  to  conditions  about 
the  hub,  but  a  propeller  built  along  these  lines  will  give 
fairly  accurate  results  for  any  amateur  who  wishes  to 
build  his  own  propeller.  All  angles  must  be  increased 
over  these  theoretical  angles  by  an  amount  equal  to  the 
slip,  that  is,  by  20  to  40  per  cent  at  the  tip. 

Propulsion   is  exerted  by  the  pressure  of  the   water 


CONSTRUCTION  AND  OPERATION  203 

against  the  driving  face  of  the  blade  and  to  obtain  the 
best  results  with  a  given  diameter  equal  work  should 
be  performed  by  every  square  inch  of  blade  surface.  That 
this  is  not  possible  will  be  seen  from  examining  the 
ineffective  area  occupied  by  the  hub  and  the  exceedingly 
heavy  blade  angles  near  the  root.  Practically  all  of  the 
work  is  done  by  the  outer  half  or  two-thirds  of  the 
blade. 

Since  the  angle  is  theoretically  90  degrees  with  the 
shaft  at  the  hub  center,  it  is  evident  that  no  drive  would 
be  experienced  at  this  point,  even  though  it  were  possi- 
ble to  dispense  with  the  hub.  This  heavy  angle  con- 
tinues for  quite  a  distance  toward  the  tips,  and  is  heavy 
enough  to  prevent  much  forward  driving  effort  for 
fully  one-third  of  the  length.  This,  coupled  with  the 
disturbing  effects  of  the  wash 'from  the  hub,  resolves 
itself  into  designing  this  part  of  the  blade  for  low  resist- 
ance to  forward  motion  rather  than  for  driving,  although 
in  some  propellers  the  angle  here  is  made  less  than  the 
theoretical  (expanding  pitch). 

A  propeller  of  the  uniform  pitch  type  is  shown  en- 
cased in  a  rectangular  block  by  Diag.  C  in  order  to  illus- 
trate such  a  propeller  more  clearly.  The  block  1-2-3-4- 
5-6-7-8  is  assumed  to  be  the  block  out  of  which  the 
propeller  pattern  is  carved,  the  widths  1-2  and  3-4  deter- 
mining the  tip  angle  ,3-2-4,  or  "a."  The  line  X-X  is 
the  center  line  of  the  hub  and  is  at  right  angles  to  the 
block  face  2-3.  A  series  of  sections  through  the  upper 
blade  are  shown  by  G,  H,  I  and  J  taken  along  the  lines 
B-B,  C-C,  D-D,  and  E-E  respectively. 

At  the  tip,  the  blade  angle -is  "a,"  this  being  the  angle 
made  by  the  blade  with  the  face  2-3  of  the  block.  Further 
down  and  on  the  line  B-B  is  the  section  G  which  makes 
the  angle  "b''  with  the  block  face.  The  angles  c,  d,  and 
e  are  taken  in  the  same  way,  increasing  as  the  root  is 
approached,  while  the  angle  F  made  by  the  section  J  with 


• 

204  MOTOR  BOATS: 

\ 

the  shaft  center  line  X-X,  is  very  nearly  at  a  right  angle 
with  the  block  face  2-3. 

In  making  a  propeller  pattern  a  block  is  chosen  whose 
length  is  equal  to  the  propeller  diameter,  as  shown  and 
whose  width  is  equal  to  the  widest  part  of  the  face.  The 
length  of  the  blade  from  the  center  line  X-X  to  the  tip  is 
then  divided  into  a  number  of  equal  parts  as  at  G,  H,  I, 
and  J,  along  the  blade  center  line  Y-Y.  These  spaces 
should  not  much  exceed  two  inches  for  accurate  work 
on  small  propellers,  and  preferably  should  be  less.  After 
the  proper  angles  are  computed  for  these  points,  saw 
cuts  are  made  along  the  section  lines  such  as  B-B,  C-C, 
etc.,  at  the  given  angle.  It  is  now  a  simple  matter  to 
chip  out  the  wood  between  the  saw  cuts  and  work  the 
blades  down  to  the  proper  form. 

In  getting  the  angles,  first  determine  the  number  of 
section  points  required  for  the  length  of  blade,  and  then 
lay  out  a  series  of  triangle  diagrams  as  shown  in  Fig.  1. 
The  base  will  be  equal  to  the  circumference  of  propeller, 
or  equal  to  3.1416  times  the  diameter.  The  vertical 
height  of  triangle  will  of  course  be  equal  to  the  actual 
pitch,  the  method  by  which  this  is  determined  being  de- 
scribed elsewhere  in  this  chapter. 

Propeller  Data. 

The  pitch  ratio,  which  is  equal  to  the  pitch  divide/a  by 
the  wheel  diameter,  depends  upon  the  type  of  boat  on 
which  the  wheel  is  to  be  used.  A  heavy  boat  with  blunt 
lines  fore  and  aft  requires  a  small  pitch  ratio,  from  1.1 
to  1.3,  with  broad  blades  and  a  low  speed  motor.  A 
medium  weight  boat  with  moderately  fine  lines  requires 
a  medium  pitch  propeller  with  a  pitch  ratio  of  from  1.4 
to  1.6.  A  speed  boat  with  a  high  speed  engine,  shallow 
draft,  narrow  fine  lines,  and  of  the  racing  type  requires 
a  pitch  ratio  of  1.8  to  2.0. 

It  should  be  remembered  in  this  connection  that  the 


CONSTRUCTION  AND  OPERATION 


205 


pitch  is  equal  to  the  diameter  multiplied  by  the  pitch 
ratio.  Thus  the  pitch  of  a  16  inch  propeller  with  a  pitch 
ratio  of  2  is  equal  to  16x2  or  32  inches.  The  pitch  ratios 
offered  by  firms  handling  stock  wheels  runs  from  1.10 
to  2,  the  former  being  for  towing  while  the  latter  is  spe- 
cially adapted  for  racing  hydroplanes.  These  sizes  cover 
the  commercial  range. 

The  ratio  of  blade  width  to  the  diameter  of  the  wheel 
varies  but  slightly  in  any  type,  say  from  0.25  to  0.40. 

With  the  exception  of  the  towing  wheel  which  has  tri- 
angular blades,  the  wheels  listed  above  are  of  the  true 
screw  type  with  elliptical  tips. 

Pitch  and  Power. 

The  power  consumed  varies  with  the  pitch,  wheel 
diameter,  and  number  of  blades,  an  increase  in  any  of  the 
three  items  resulting  in  greater  power  consumption. 
Roughly  speaking  a  three  blade  propeller  will  absorb 
approximately  1.5  times  as  much  power  as  the  same  size 


Type  of  Wheel 

Pitch 
Ratio 

Boat  Type 

Blade 

Width 
fcDiam. 

Type 
Engine 

•  Towing 

1.10 

Heavy-Slow 

33 

Slow  Speed 

General    Use 

1.40 

Yachts-Launch 
Fast   Work   Boat 

25 

Moderate  Speed 

1.50 

Runabouts 

25 

High   Speed 

Speed 

1.60 

Runabouts  and 
Small  Racers 

30 

High  Speed 

Speed 

1.80 

Large  Racers 

33 

Great  Power 

Speed 

2.00 

Hydroplanes 
Light    Draft 

33 

Great  Power 
High   Speed 

of  two  blade  wheel.  The  pitch  increases  the  power  at  a 
rapid  rate.  A  small  diameter  wheel  will  not  transmit 
as  much  power  at  low  speed  as  at  high,  since  the  pres- 
sure per  unit  of  blade  area  is  greater  at  the  lower  speed. 
Within  certain  limits,  the  power  transmitted  by  a  given 
wheel  is  in  direct  proportion  to  the  revolutions  per  min- 


806  MOTOR  BOATS: 

ute,  that  is,  doubling  the  speed  gives  twice  the  propelling 
power. 

With  a  broad  skeg  or  thick  deadwood^  two  bladed 
propeller  transmits  less  power  than  a  wheel  with  three 
blades  since  the  supply  of  water  is  momentarily  cut  off 
from  the  two  blades  when  they  stand  in  a  vertical  posi- 
tion. With  a  three  blade  wheel  there  will  always  be  two 
blades  effective  in  driving,  no  matter  what  the  position  of 
the  wheel.  A  two  blade  wheel  acts  on  a  greater  volume 
of  water  at  high  speed  for  with  three  the  water  does  not 
pass  freely  between  the  blades. 

With  a  boat  having  full  lines  aft  care  should  be  taken 
not  to  have  the  pitch  too  great  as  a  high  pitch  tends  to 
scoop  out  the  water  from  under  the  stern  and  causes  the 
boat  to  "Squat." 

In  fitting  propellers,  especially  to  racing  boats,  it  will 
often  be  found  that  the  diameter  is  too  great  to  allow  the 
motor  to  run  at  its  rated  speed.  The  reduction  in  the 
motor  speed  will  of  course  prevent  the  engine  from  devel- 
oping its  full  power,  and  from  giving  the  necessary  pitch 
velocity.  To  reduce  the  drag  and  to  allow  the  motor  to 
speed  up,  the  diameter  can  be  cut  down  if  the  same 
shape 'and  proportion  of  the  blade  is  maintained.  That 
is,  if  the  width  is  reduced  in  the  same  proportion.  This 
does  not  change  the  efficiency  to  any  great  extent  in  a 
true  screw  propeller. 

In  regard  to  cutting  down  a  wheel  it  must  be  remem- 
bered that  the  blades  must  not  be  twisted  so  as  to  change 
the  pitch  and  on  the  completion  of  the  job  that  the  wheel 
must  be  perfectly  balanced.  All  blades  must  be  of  equal 
thickness  at  the  same  point  and  there  must  be  no  differ- 
ence in  pitch  between  the  blades.  Unbalanced  wheels, 
blades  of  unequal  length  or  thickness,  unequal  pitch,  or 
very  thin  blades  will  produce  annoying  and  destructive 
vibration,  especially  at  high  speeds. 


CONSTRUCTION  AND  OPERATION  207 

Horse-Power  Tables. 

The  accompanying  tables  will  give  the  approximate 
horsepowers  corresponding  to  various  pitch  ratios,  diam- 
eters, and  numbers  of  blades  and  for  different  classes  of 
service.  In  the  first  four  columns  will  be  found  the 
"Type  of  boat,"  "pitch  ratio,"  and  the  "pitch  correspond- 
ing to  a  given  pitch  ratio  and  diameter."  Thus  a  wheel 
for  a  towing  boat  with  a  pitch  ratio  of  1.10  and  a  diameter 
of  20  inches  will  have  a  corresponding  pitch  of  22  inches. 
The  next  four  columns  are  the  horsepowers  for  two  and 
three  blade  wheels  at  both  the  maximum  rated  speed  and 
at  100  revolutions  per  minute.  Taking  a  20  inch  wheel 
with  a  pitch  ratio  of  1.10  it  will  be  seen  that  a  two  blade 
wheel  will  absorb  2.25  H.  P.  at  100  revolutions  and  that 
the  same  pitch  and  diameter  in  a  three  bladed  wheel  will 
absorb  3  H.  P.  at  the  same  speed. 

At  400  revolutions  per  minute  (the  rated  speed),  the 
the  power  required  will  be  four  times  as  much,  or  9  and 
12  H.  P.  respectively.  For  any  other  speed  not 
greatly  in  excess  of  400  revolutions,  multiply  the  power 
at  100  revolutions  by  the  number  of  hundreds  of  revolu- 
tions. Thus  if  the  two  bladed  20  inch  wheel  is  to  be 
driven  at  350  revolutions,  the  power  will  be  2.25x3.5 
=  7.9  H.  P.,  approximately.  In  this  case  the  figure  3.5 
stands  for  three  and  one-half  hundreds.  Since  the  maxi- 
mum revolutions  in  this  case  are  400  per  minute,  the 
column  "HP  At  Max.  Revs."  gives  values  four  times  as 
great  as  those  in  the  first  column. 

Example:  We  desire  to  drive  a  boat  25  miles  per 
hour,  and  from  towing  tests  on  this  boat  we  find  that  50 
H.  P.  will  be  required  to  drive  this  particular  hull 
through  the  water.  We  will  assume  a  slip  of  20  per  cent 
and  an  engine  speed  of  800  revolutions  per  minute.  Find 
the  approximate  size  of  propeller  required. 

With  a  20  per  cent  slip,  the  actual  pitch  speed  will  be 


208 


MOTOR  BOATS: 


POWER  REQUIRED  FOR  PROPELLERS 


Purpose 

Pitch 
Ratio 

Corresponding 
Pitch 

Pitch  Diam.  < 

Two  Blades    Three  Blades 

H.  P.     H.  P. 
it  100  at  Max. 
Revs.   Revs. 

H.  P.    H.  P. 
at  100  at  Max. 
Revs.    Revs. 

Towing 

1.10 
Max. 
Revs. 

400 

17.6 
19.8 
22.0 
24.2 
26.4 
30.8 
32.3 
39.3 

16.0 
18.0 
20.0 
22.0 
24.0 
28.0 
30.0 
36.0 

1.00 
1.50 
2.25 
3.00 
4.00 
7.50 
9.00 

4.00 
6.00 
9.00 
12.00 
16.00 
30.00 
36.00 

1.50 
2.25 
3.00 
4.00 
6.00 
9.00 
10.00 
15.00 

6.00 
9.00 
12.00 
16.00 
24.00 
36.00 
40.00 
60.00 

Speed 
(Medium  Wt.) 

1.30 
Max. 
Revs. 

400 

18.2 
20.8 
23.4 
26.0 
28.6 
31.2 
33.8   ' 
36.4 
39.0 

14.00 
16.00' 
18.00 
20.00 
22.00 
24.00 
26.00 
28.00 

3aoo 

0.66 
1.00 
1.50 
2.25 
3.00 
4.00 
6.00 

2.50 
4.00 
6.00 
9.00 
12.00 
16.00 
24.00 

0.75 
1.25 
2.25 
3.00 
4.00 
6.00 
7.50 
9.00 
10.00 

3.00 
5.00 
9.00 
12.00 
16.00 
24.00 
30.00 
36.00 
40.00 

All  Around 
Wheel 

(Yachts- 
Launches) 

1.40 
Max. 
Revs. 
400 

16.8 
19.6 
22.4 
25.2 
28.0 
30.8 
33.6 
39.2 
42.00 
50.40 

12.00 
14.00 
16.00 
18.00 
20.00 
22.00 
24.00 
28.00 
30.00 
36.00 

0.40 
0.60 
1.00 
1.50 
2.25 
3.00 
4.00 
7.50 
9.00 
12.00 

1.60 
2.40 
4.00 
6.00 
9.00 
12.00 
16.00 
30.00 
36.00 
48.00 

1.25 
3.00 
4.00 
6.00 
7.50 
9.00 
10.00 
15.00 
20.00 
30.00 



Racing 
Boats 
Only 

1.8 
Max. 
Revs. 

800 

21.6 

25.2 
28.8 
32.5 
36.0 
43.2 
46.8 

12 
14 
16 
18 
20 
24 
26 

0.38 
0.75 
1.25 
2.13 
3.63 
'9.13 
13.75 

3.0 
6.0 
10.0 
17.0 
29.0 
73.0 
110.0 

0.57 
1.00 
1.75 
3.00 
5.00 
12.50 
19.38 

4.5 
8.0 
14,0 
24.0 
40.0 
100.00 
155.00 

Hydroplanes 

2 
Max. 
Revs. 
1000 

24.0 
28.0 
32.0 
36.0 
40.0 
44.0 
48.0 

12.0 
14.0 
16.0 
18.0 
20.0 
22.0 
24. 

0.60 
1.00 
1.50 
2.50 
4.00 
6.00 
7.50 

6.00 
10.00 
15.00 
25.00 
40.00 
60.00 
75. 

.80 
1.20 
2.00 
3.50 
5.00 
7.50 
12.00 

8.00 
12.00 
20.00 
35.00 
50.00 
75.00 
120.00 

CONSTRUCTION  AND  OPERATION  209 

1  1/5  times  25,  or  30  Miles  per  hour.    At  800  revolutions 
the  pitch  will  be, 
P          Miles  per  Hour  30 

= = =  40  inch 

.000947  X  N  .000947  X  800 

pitch,  where  P  is  the  pitch,  and  N  is  the  number  of  revo- 
lutions per  minute.  (  See  speed  table.)  As  this  is  a 
speed  boat  the  pitch  ratio  will  be  from  1.8  to  2:0. 

Consulting  the  power  table  and  with  a  pitch  ratio  of 
1.8,  we  find  that  the  nearest  pitch  is  43.2  inches,  and  that 
the  diameter  is  24  inches.  Following  to  the  right  we 
find  that  a  two  bladed  propeller  of  this  size  will  transmit 
73  H.  P.  This  is  ample  for  our  needs  but  it  is 
possible  that  it  will  slow  down  the  engine  so  that  the 
full  speed  will  not  be  available.  The  next  size  smaller 
will  give  36  inch  pitch,  29  H.  P.  with  two  blades 
and  40*  H.  P.  with  three  blades,  both  wheels  being 
too  small  although  the  three  blade  wheel  would  allow 
the  engine  to  speed  up  and  gain  power.  Since  the  power 
is  in  proportion  to  the  speed,  the  speed  of  the  wheel  would 
be  increased  25  per  cent  since  the  power  increase  will  be 
25  per  cent.  We  could  use  this  wheel  if  it  would  be  per- 
missible to  run  our  engine  at  1,000  revolutions. 

Assuming  a  pitch  ratio  of  2.0  a  20  inch  wheel  will  have 
40  inch  pitch,  and  absorb  50  H.  P.  at  1,000  revolu- 
tions, or  the  same  pitch  ratio  with  a  22  inch  wheel  will 
give  44  inch  pitch  and  will  absorb  60  H.  P.  (Two  blades.) 
Since  60  H.  P.  is  1.2  X  50  H.  P,  the  latter  wheel  will 
transmit  50  H.  P.  at  20  per  cent  less  speed,  or  800  revolu- 
tions, the  required  speed.  The  pitch  will  also  be  reduced 
20  per  cent  or  to  35.2  inches,  a  little  low. 

As  every  engine  can  develop  considerably  over  its 
rated  power  wre  can  run  a  24  inch  diameter,  48  inch  pitch 
propeller  at  800  revolutions  which  will  make  the  effective 
output  60  H.  P.  instead  of  75  as  shown  and  the  effective 
pitch  will  be  38.4  inches. 


210 


MOTOR  BOATS: 


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CHAPTER  XVIII 

REVERSING  GEAR  AND  PROPELLER  WHEELS. 

A  motor-boat  which  is  not  equipped  with  some  means 
of  backing  up  lacks  an  important  factor  of  safety  and 
convenience.  Most  owners  nowadays  require  a  reversing 
device,  and  there  are  various  methods  employed  for  the 
purpose.  Where  a  reverse  gear  is  installed  the  boatman 
enjoys  the  advantages  of  positive  control  of  a  forward 
and  backward  movement  to  the  boat  and  also  of  a  neutral 
point.  Racing  rules  usually  require  power  craft  to  be  pro- 
vided with  means  of  changing  positively  and  quickly  from 
full  speed  ahead  to  full  speed  astern,  this  point  being 
strongly  insisted  upon. 

Reversing  the  direction  of  a  boat  may  be  accomplished 
by  reversing  the  engine  itself,  by  the  use  of  the  switch, 
but  to  do  this  successfully  requires  practice  and  con- 
siderable aptitude  on  the  part  of  the  operator.  The  two 
more  direct  methods  generally  used  are  a  reverse  gear 
or  a  reversible  propeller. 

A  reversing  gear  is  a  system  of  clutches  and  toothed 
wheels  by  means  of  which  the  propeller  shaft  may  be 
made  to  turn  either  opposite  to  or  in  the  same  direction  as 
the  motor  crankshaft.  The  reversing  gear  uses  a  solid 
propeller,  which  may  be  made  stronger  than  a  reversing 
propeller  wheel,  and  can  take  more  hard  blows  and 
knocks  without  breaking,  but  its  great  advantage  is  that 
it  places  the  reversing  mechanism  inside  the  boat,  where 
it  is  less  liable  to  meet  with  mishap  and  is  accessible  for 
repair  in  case  anything  does  happen. 

There  are  countless  instances  where  it  is  necessary  to 
bring  a  boat  to  a  quick  stop,  reverse  or  slow  down,  then 


212  MOTOR  BOATS: 

go  ahead,  and  to  perform  these  operations  repeatedly. 
When  operating  a  boat  in  crowded  waters  "or  making  a 
dock,  the  feeling  that  one  has  a  reliable  reverse  gear 
coupled  to  the  propeller  shaft  gives  the  wheelsman  con- 
fidence in  his  craft,  which  is  wholly  lacking  when  his  boat 
is  not  equipped  properly  for  reversing. 

Another  feature  in  favor  of  a  reverse  gear  equipment, 
just  as  important  as  the  forward  and  backward  control, 
if  not  more  so,  is  the  neutral  point. 


Ferro  Reverse  Gear. 

When  the  reverse  gear  is  thrown  into  a  neutral  posi- 
tion the  motor  may  be  running,  but  this  motion  is  not 
transmitted  to  the  propeller,  or  in  other  words  the  motor 
may  be  going  without  the  boat  moving  at  all. 

'This  is  a  very  desirable  point,"  says  a  well  known 
authority,  "for  the  following  reasons:  First.  If  you 
wish  for  any  reason  to  try  out  your  motor  to  see  how 
it  is  working,  with  a  reverse  gear  equipment  you  may 
run  your  motor  just  as  long  and  at  any  speed  you  wish 


CONSTRUCTION  AND  OPERATION  213 

without  ever  putting  out  from  the  boathouse  or  land- 
ing, and  without  having  lines  out  from  "bow  and  stern 
to  hold  the  boat  stationary. 

"Second.  Often  for  various  causes  the  boat  is  stopped 
for  such  a  very  short  time,  too  short  a  time  really  to 
shut  the  motor  down ;  with  a  reverse  gear  the  motor 
may  continue  to  run  while  the  forward  movement  of 
the  boat  is  stopped. 


Parts  of  Ferro  Reverse  Gear. 

"Third.  Probably  the  very  best  reason  of  all  for  in- 
stalling a  reverse  gear  is  ease  of  starting.  By  throwing 
the  reversing  gear  into  the  neutral  position,  the  effort 
required  to  turn  over  the  flywheel  of  the  motor  when 
starting  is  very  greatly  lessened.  Without  a  reversing 
gear  it  is  necessary  when  starting  a  motor  to  turn  over 
not  only  the  flywheel  and  crankshaft  of  the  motor,  but 
the  propeller  shaft  and  propeller  in  the  water. 

"When  an  automobile  is  started  the  engine  alone  is 
started  first  before  taking  up  the  load  of  operating  the 
car.  This  same  idea  is  carried  out  in  most  machinery 
plants,  that  is,  the  load  is  not  placed  on  the  engine  or 
motor  until  it  is  fairly  started.  Why  should  it  be  other- 
wise in  a  boat,  especially  when  the  motor  used  is  of 
fairly  large  size? 

"The  advisability  of  installing  a  reverse  gear  being 
hardly  disputed,  the  question  to  take  up  is  the  kind  of 
gear  to  use.  Like  all  mechanical  devices,  a  poor  reverse 
gear  is  worse  than  none  at  all. 

"Some  of  the  points  desirable  in  a  reverse  gear  are  the 
following : 


314  MOTOR  BOATS: 

"The  good  reversing  gear  should  couple  the  motor  di- 
rectly to  the  motor  shaft  on  the  forward  drive;  there 
should  be  no  gears  running,  and  the  whole  device  should 
act  simply  as  an  extra  flywheel  or  a  straight  unbroken 
shaft.  To  carry  the  power  through  gearing  on  the 
forward  drive  is  often  wasteful  and  noisy.  'When  the 
gear  is  in  the  neutral,  the  motor  runs  free,  without  turn- 
ing the  propeller  shaft;  it  makes  no  difference  whether 
the  gears  run  or  not,  as  there  is  no  load  on  them  and 
therefore  no  wear.  On  the  reverse  position,  the  gears 
come  into  play  and  the  power  of  the  motor  is  transmitted 
and  reversed  by  them.  The  gears  should  be  'in  mesh' 
with  the  motor  running.  The  changes  from  the  neutral 
into  the  forward  speed  or  from  neutral  into  the  reverse 
should  be  so  arranged  that  the  load  is  picked  up  grad- 
ually without  a  jerk.  All  brakes,  clutches,  and  other 
parts  should  be  easily  adjusted  and  all  gears  should  have 
bushings  running  on  steel  pins ;  the  wear  will  then  come 
on  the  bushings,  which  cost  about  one-tenth  the  price 
of  spur  gears. 

"Gears  should  be  of  ample  diameter,  and  stub  tooth 
pattern.  They  should  be  inclosed  in  an  oil-tight  case, 
which  can  be  rilled  with  oil  or  packed  with  grease  as  may 
be  required.  The  entire  gear  ought  to  have  a  rigid  fore 
and  aft  bearing." 

Reversible  Propellers. 

With  a  reverse  gear,  when  it  is  reversed,  the  propeller 
shaft  turns  opposite  to  the  motoj  shaft.  With  a  reversible 
propeller,  when  it  is  reversed,  the  angle  of  the  propeller 
blades  is  changed  so  as  to  pull  the  boat  backward. 

If  the  propeHer  blades  are  to  change  their  angle  they 
must  turn  in  the  hub;  but  as  the  diameter  of  the  hub 
of  a  motor-boat  wheel  is  small,  it  must  be  hollow  to  con- 
tain the  device  for  shifting  the  blades  and,  if  possible, 
it  should  present  a  smooth  exterior.  To  fasten  three 
blades,  or  even  two,  to  the  small  hub,  to  get  them  so 


CONSTRUCTION  AND  OPERATION  215 

that  they  will  turn  easily  when  there  is  a  pressure  on 
them,  to  have  no  play  and  plenty  of  bearing  surface  to 
prevent  wear,  is  not  an  easy  matter,  because  there  is  so 
little  room  on  the  hub  or  inside  of  it. 

The  fastening  of  the  blades  to  the  hub  is  the  vital 
point ;  the  rest  is  easy.  The  usual  method  of  construction 
is  to  make  the  propeller  shaft  in  two  parts:  an  inside, 
solid  shaft,  driven  by  the  motor  and  keyed  to  the  hub, 
and  a  hollow  tube  outside  this  shaft,  which  is  shifted 


Reversible  Propeller. 

forward  and  aft  by  the  lever  inside  the  boat.  The  shaft 
terminates  in  the  hub,  in  which  the  propeller  blades  are 
pivoted.  The  tube  terminates  in  a  yoke  which  engages 
a  lug  or  pin  on  each  blade,  and  serves  to  shift  the  angle 
or  pitch  of  the  blades,  when  the  propeller  is  either  idle 
or  in  operation,  hence  giving  the  propeller  a  forward  or 
reverse  pitch. 

The  great  advantage  of  a  reversible  propeller  is  the 
splendid  control  you  have  over  the  speed  of  the  boat, 
from  practically  nothing  at  all  up  to  full  speed  in  either 


216  *         MOTOR   BOATS: 

direction.  The  fisherman  who  trolls  with  his  launch 
finds  the  reverse  propeller  advantageous  for  maintaining 
the  slow  forward  motion  which  trolling  requires.  For 
other  similar  purposes  the  reverse  propeller  has  its 
merits. 

With  the  advent  of  auxiliary  power  in  small  and  large 
sailboats,  there  has  arisen  a  demand  for  a  propeller 
which,  when  the  boat  is  under  sail,  will  not  have  any  re- 
sisting tendencies  in  retarding  the  forward  motion  of  the 
boat.  Several  reversible  propellers  on  the  market  are 
therefore  designed  so  that  the  blades  can  be  turned  edge- 
wise. This  is  termed  a  "feathering"  blade.  Where  this 
type  of  reversible  wheel  is  constructed  to  give  the 
strength  and  serviceability  that  is  required,  and  to  with- 
stand severe  usage,  it  can  be  used  to  good  advantage  by 
the  yachtsman  and  the  fisherman. 

The  reversible  propellers  furnished  when  desired  with 
the  well  known  Buffalo  engines  are  illustrated  herewith. 
They  are  made  with  round  closed  hub  and  smooth  sur- 
face, creating  the  least  possible  disturbance  of  water  and 
not  entangling  with  weeds  as  easily  as  the  open  type. 
All  parts  are  accurately  machined  and  interchangeable. 
They  are  made  of  a  very  superior  bronze  .which  is  ex- 
tremely tough. 


Buffalo  Reversible  Propeller,  Showing  Hub,  etc. 


CHAPTER  XIX 
HYDROAEROPLANES 

Early  in  the  history  of  aviation  it  was  found  desirable 
to  conduct  flying  experiments  over  water  in  order  to 
minimize  the  danger  of  such  work  and  also  to  obtain 
a  smooth  surface  for  making  the  preliminary  run.  This 
demand  led  to  the  development  of  the  hydro-aeroplane 
or  flying  boat,  which  is  simply  an  aeroplane  provided 
with  floats  or  pontoons  of  the  planing  type  just  described. 
Owing  to  the  efficiency  of  these  hulls  in  regard  to  power 
consumption  and  weight  they  deserve  more  than  passing 
notice  even  to  those  not  particularly  interested  in  flying. 

In  general  these  hulls  may  be  divided  into  three  prin- 
cipal classes:  (1)  The  single  pontoon;  (2)  the  double 
pontoon  ;  (3)  a  pontoon  in  which  is  located  the  passengers 
and  sometimes  the  power  plant.  The  latter  type  gener- 
ally is  referred  to  as  a  "Flying  Boat."  In  the  first  two 
classes  the  passengers  and  power  plant  are  carried  in  the 
body  of  the  aeroplane  proper,  the  pontoons  merely  taking 
the  place  of  the  usual  chassis  wheels  and  act  as  a  support 
for  the  aeroplane.  In  all  cases  the  drive  is  by  an  aerial 
propeller  whether  the  plane  is  moving  on  the  water  or  in 
flight. 

A  hull  of  the  first  type  is  shown  by  Fig.  1,  and  is  com- 
monly used  in  the  Curtiss  and  Farman  machines,  the 
wings  and  aeroplane  structure  being  shown  above  the 
hull.  To  prevent  excessive  strains  due  to  hard  landings 
it  is  now  common  practice  to  provide  rubber  cable  shock 
absorbers  located  on  the  supporting  members.  As  the 
hull  is  very  narrow  the  side  balance  is  accomplished  by 
the  wing  surfaces  when  at  speed,  small  floats  at  the  wing 
tips  serving  to  hold  the  machine  upright  when  at  rest. 


218 


MOTOR  BOATS. 


CONSTRUCTION  AND  OPERATION  S19 

To  lift  the  hull  out  of  water  at  the  critical  flying  speed, 
the  tail  surfaces  are  depressed  so  that  the  planes  tip  up 
in  front  and  therefore  raise  the  nose  of  the  hull.  A  con- 
structional detail  of  the  Curtiss  pontoon  construction  is 
shown  by  Fig.  3  which  gives  the  arrangement  of  the  ribs 
and  form  of  the  surfaces.  The  hull  is  of  a  very  thin 
veneer  and  is  extremely  light.  A  pair  of  battens  are 
placed  on  the  planing  bottom  to  prevent  injury  in  beach- 
ing the  machine.  Fig.  2  is  a  larger  and  more  elaborate 
form  used  on  the  French  Breguet  Biplane.  It  will  be 
noted  that  the  bow  is  more  nearly  of  the  conventional 
boat  type  than  in  the  preceding  example. 

Fig.  5  shows  a  Burgess-Wright  double  pontoon  type 
of  the  biplane  order,  the  double  aerial  screws  being  shown 
behind  and  between  the  two  wing  surfaces.  The  pas- 
sengers and  the  power  plant  are  carried  in  the  "Nacelle" 
attached  to  the  lower  plane.  As  the  two  pontoons  are 
placed  at  a  considerable  distance  from  one  another  no 
floats  are  required  on  the  wing  tips  and  no  special  bal- 
ancing is  required  when  planing  over  the  water.  Double 
pontoons  have  the  disadvantage,  however,  of  offering 
considerable  air  resistance  when  in  flght  and  of  being 
unstable  in  rough  water.  In  rough  water  strain  is  occa- 
sioned in  the  frame  by  the  floats  striking  waves  of  differ- 
ent height  at  the  same  instant,  especially  when  running 
in  the  trough  of  the  sea.  This  trouble  is  much  reduced 
with  single  .pontoons. 

Fig.  4  shows  the  well  known  Curtiss  Flying  Boat,  a 
type  in  which  the  aviator  and  passenger  are  located  in  the 
hull  with  the  power  plant  well  up  between  the  wings. 
This  hull"  is  of  the  "stepped  type."  The  step  in  this  case 
is  about  two  inches,  while  the  side  drift  due  to  the  wing 
surfaces  is  partially  offset  by  the  thin  keel  shown  in  the 
center  of  the  planing  surface.  With  a  side  wind,  or  in 
rough  water,  the  machine  is  prevented  from  tipping  side- 
ways when  at  rest  by  the  small  cylindrical  metal  floats 


220 


MOTOR  BOATS: 


CONSTRUCTION  AND  OPERATION 


221 


shown  at  the  tips  of  the  lower  wing.  When  in  flight  or 
when  running  rapidly  over  the  water  balance  is  affected 
by  the  "Aileron"  or  small  movable  surface  shown  midway 
between  the  main  planes  and  at  the  tip.  The  horizontal 
line  shown  under  the  wings  is  the  center  line  of  air 


FIG.  4   (Above).— Shows  the   Curtiss   Flying   Boat. 
FIG.  5  (Below). — Burgess  Wright  Double  Pontoon  Type. 

pressure  on  the  wings  which  is  normally  located  near  the 
center  of  gravity.  The  step  is  generally  located  slightly 
behind  this  point  as  shown.  At  the  extreme  rear  end  is 
the  tail  surface  used  in  maintaining  fore  and  aft  balance 
and  for  elevating  the  machine  into  the  air  after  the  flying 
speed  has  been  reached. 

In  the  majority  of  cases  both  the  flying  boat  hulls  and 
the  pontoons  are  provided  with  several  water  tight  com- 
partments to  protect  the  plane  when  the  hull  is  sprung 


222 


MOTOR  BOATS: 


CONSTRUCTION  AND  OPERATION  223 

by  a  hard  landing  or  by  striking  a  snag.  As  the  body  of 
the  hull  is  necessarily  of  very  frail  construction  great 
care  must  be  exercised  in  landing  and  maneuvering  on 
the  water  to  prevent  leakage  and  misalignment  of  the 
flying  surfaces.  The  power  for  flying  this  type  is  sup- 
plied by  a  motor  rarely  less  than  125  H.  P.,  and  in 
several  recent  war  machines  in  excess  of  400  H.  P. 
United  States  Government  specifications  generally  call 
for  sufficient  fuel  to  make  a  continuous  six  hour  flight  and 
sufficient  capacity  for  the  carrying  of  an  observer.  This 
brings  the  total  weight  well  over  3000  pounds  for  a  war 
hydro-aeroplane.  The  speed  is  approximately  80  miles 
per  hour.  A  recent  Siborowski  plane  built  for  the 
Russian  government  carries  two  300  H.  P.  motors  and 
carries  a  useful  load  of  over  6000  pounds. 

The  large  battle  planes  and  long  range  reconnaissance 
type  seaplanes  used  by  the  United  States  Government 
are  provided  with  "Twin"  motors,  each  motor  carrying 
a  separate  propeller.  The  motors  are  carried  on  either 
side  of  the  central  body  about  half-way  out  on  the  wings. 
Two  engines  and  two  propellers  are  made  necessary 
by  the  fact  that  it  is  very  difficult  to  build  a  satisfac- 
tory propeller  that  will  transmit  more  .than  160  horse- 
power. By  subdividing  the  power  plant  into  two  units 
it  is  possible  to  transmit  300  horsepower  total,  with 
ease. 

In  case  of  accident,  the  twin  can  fly  on  one  motor, 
although  this  throws  an  eccentric  load  on  the  machine 
that  must  be  constantly  corrected  with  the  rudder.  On 
account  of  the  heavy  motors  placed  at  a  considerable  dis- 
tance from  the  center  of  gravity,  the  twin  has  consid- 
erable inertia  and  is  sluggish  and  "logy"  in  answering 
the  controls.  This,  however,  is  not  so  much  of  a  dis- 
advantage with  a  sea  plane  as  with  a  land  machine. 

On  page  222  is  shown  a  hydroaeroplane  of  the  "mono- 
plane" type  in  which  there  is  only  a  single  set,  or  "layer" 


224  MOTOR  BOATS: 

of  wings.  As  this  type  of  machine  has  not  much  wing 
area  it  cannot  support  much  of  a  load  except  at  ex- 
tremely high  speeds.  For  high  speed  work,  the  mono- 
plane is  an  excellent  machine  and  is  used  extensively 
in  scouting  work  and  in  combat  service  where  enemy 
aeroplanes  must  be  driven  off.  For  bomb  carrying  or 
other  heavy  work  they  are  useless. 

The  cut  of  the  monoplane  gives  an  excellent  idea  of 
the  position  of  the  pontoons  when  the  machine  is  just 
about  to  leave  the  water.  The  bearing  on  the  water  is 
well  to  the  rear  of  the  pontoons,  and  a  little  further  in- 
crease in  the  angle  of  the  wings  will  "break  her  loose." 


CHAPTER  XX 

ENGINE  TROUBLES  AND  THEIR  REMEDIES. 

A  thorough  understanding  of  the  engine  will  often 
enable  the  owner  to  prevent  trouble.  Most  engines 
have  their  own  peculiar  idiosyncrasies  and  the  consci- 
entious owner  will  carefully  study  his  motor  and  ascer- 
tain the  conditions  necessary  for  its  operation.  When 
he  is  thoroughly  familiar  with  it,  if  he  cannot  always 
prevent  trouble  he  will  be  better  able  to  detect  and 
rectify  it. 

Engine  faults,  causing  deficiency  of  power  or  inability 
to  start,  may  be  divided  into  three  classes:  Mechanical 
troubles,  ignition  troubles  and  carbureter  troubles,  or 
those  due  to  faulty  mixture. 

Mechanical  troubles  include  those  that  may  be  in- 
cluded under  the  heads  of  Poor  Compression,  Weak  or 
Broken  Valve  Springs,  Valve  Timing  and  Pipe  Ob- 
structions and  Leaks. 

The  great  majority  of  engine  troubles  may  be  charged 
up  to  ignition.  Ignition  troubles  are  easily  distinguished 
from  those  due  to  imperfect  mixture.  If  the  spark  fails 
or  is  very  weak,  the  charge  is  not  ignited  at  all.  If  the 
sparks  are  regular,  too  much  or  too  little  gasolene  in  the 
mixture  will  make  the  engine  run  weak,  but  there  will 
be  no  misfiring  unless  the  mixture  is  very  bad  indeed. 
If  the  explosions  which  occur  are  reasonably  strong,  the 
cause  of  misfiring  is  to  be  looked  for  in  the  ignition. 

If  the  engine  owner  or  operator  has  familiarized  him- 
self with  the  principles  and  adjustment  of  his  carbureter, 
or  mixing  valve,  he  will  soon  learn  what  to  do  in  case 


226  MOTOR  BOATS: 

of  trouble  with  the  engine  when  the  symptoms  indicate 
defective  mixture. 

The  most  common  engine  troubles  and  their  symptoms, 
may  be  very  briefly  summed  up  as  follows : 

Failure  to  Start. — Too  much  or  no  gasolene,  or  no 
spark  at  the  plug. 

Base  Explosions. — Not  enough  gasolene;  or  too  late 
a  spark. 

Pounding. — Generally  a  loose  flywheel,  or  too  early 
a  spark. 

Failure  to  Reverse. — Probably  too  much  gasolene 
turned  on,  speed  not  caught  right,  or  weak  batteries. 

Missing  Explosions. — Defective  spark  plug,  water  in 
cylinder,  poor  contact  at  cam,  weak  batteries,  too  much 
gasolene,  or  vibrator  of  coil  sticking. 

How  to  Remedy  Troubles. 

In  the  following  pages  the  symptoms  of  and  remedies 
for  all  the  troubles  likely  to  be  experienced  in  operating 
a  marine  gasolene  engine  are  clearly  indicated. 

Leaks. 

See  that  gasket  is  sound  and  no  leakage  from  crank- 
case. 

See  that  spark  plug  is  screwed  in  tight,  so  there  is  no 
leakage  around  threads. 

See  that  valves  in  carbureter  seat  properly. 
Stops. 

Regulate  flow  of  fuel  so  there  is  no  flooding  or  starving. 

See  that  commutator  is  in  tune  with  fuel  supply. 

See  that  spark  is  healthy,  causing  regular  explosions. 

See  that  cylinder  is  perfectly  lubricated. 
Failure  in  Starting. 

If  the  engine  refuses  to  start  the  following  causes  are 
possible : 

1.  Switch  not  closed.  x 

2.  Gasolene    shut    off;    too    much    or    not    enough 
gasolene. 


COXSTRUCTIOX  AND  OPERATIOX  227 

3.  Broken  wire. 

4.  Water  on  spark  plugs. 

5.  Dead  battery. 

6.  Grounded  low  tension  igniter. 

7.  Carbureter  primed  too  little  or  too  much. 

8.  Water  in  carbureter. 

9.  Stale  gasolene. 

10.     Weak  spark  or  no  spark  at  the  plug. 

If  high  tension  ignition  is  used,  turn  the  crank  slowly 
and  note  if  the  coil  tremblers  buzz.  If  not,  look  for 
broken  primary  wire  or  dead  battery.  If  ignition  is  by 
make-and-break,  short  circuit  one  of  the  igniters  by 


"Standard"  Engine,  25-32  H.  P.,  4-cycle. 
Standard  Motor  Construction  Co.,  Jersey  City,  N.  J. 

snapping  a  wire  or  screwdriver  from  the  outside  connec- 
tion to  the  engine,  and  see  if  a  spark  results.  If  the  en- 
gine has  only  one  or  two  cylinders,  short  circuit  the  (high 
tension)  spark  plugs  to  test  the  spark.  To  do  this,  touch 
a  screwdriver  to  the  cylinder,  then  approach  it  to  the 
spark  plug  binding  post.  By  doing  this  you  will  avoid 
a  shock.  The  foregoing  tests  will  indicate  whether  or  not 
the  ignition  is  at  fault.  If  it  is  not,  look  for  mixture 
troubles. 

If  the  engine  fails  to  start  after  several  trials,  too  much 
gasolene  may  be  feeding,  which  can  be  determined  by 
opening  the  air-cocks  and  turning  the  flywheel  around 


228  MOTOR  BOATS: 

slowly  with  the  switch  on  until  an  explosion  takes  place 
through  the  air-cocks,  then  close  them  and  start  as  before. 

It  very  frequently  happens  that  an  engine  becomes 
flooded  with  gasolene  by  allowing  it  to  stand  with  the 
gasolene  valves  open,  so  the  gasolene  can  work  in  and 
lie  in  the  base  of  the  engine.  It  will  then  be  difficult  to 
start  on  account  of  the  excess  of  gas  which  is  formed. 
To  determine  this,  open  the  cock  at  the  bottom  of  the 
engine  and  turn  the  flywheel  around  until  an  explosion 
occurs. 

Missing  Explosions. 

Defective  or  dirty  spark  plug,  water  in  cylinder,  poor 
contact  at  cam,  loose  connections  or  weak  batteries, 
sticky  vibrator  on  the  spark  coil.  Sometimes  caused  by 
feeding  too  much  gasolene.  Occasionally  the  timer  may 
give  a  poor  contact  and  cause  missing,  which  can  be 
easily  remedied  by.  putting  in  new  contact  pieces  or 
stiffer  springs. 

Base  Explosions. 

Not  enough  gasolene.  Turn  on  more  gasolene  and  set 
the  spark  a  little  earlier. 

Sudden  Loss  of  Power. 

If  the  carbureter  has  been  giving  good  service  and  the 
mixture  suddenly  goes  wrong,  do  not  attempt  to  correct 
matters  by  changing  the  carbureter  adjustment.  Look 
instead  for  stale  gasolene,  for  a  sticking  auxiliary  air 
valve  in  the  carbureter,  or  for  dirt  or  water  in  the  gaso- 
lene. If  the  carbureter  has  a  wire  gauze  intake  screen  it 
may  be  choked  with  dust.  If  the  carbureter  floods,  the 
float,  if  of  metal,  may  be  punctured,  or  if  cork,  it  may 
have  absorbed  gasolene ;  or  the  float  valve  may  leak  and 
cause  dripping.  If  the  weather  has  suddenly  turned  cold 
and  the  engine  will  not  start,  probably  a  little  hot  water 
poured  over  the  carbureter  will  evaporate  the  gasolene 
and  start  the  engine  off  as  well  as  ever. 


CONSTRUCTION  AXD   OPERATION  229 

Loss  of  Compression. 

Failure  to  hold  compression  may  be  due  to  leaky  ex- 
haust valves,  leaky  gaskets  or  leaky  piston  rings.  An 
extra  dose  of  oil  on  the  piston  head  will  make  the  rings 
temporarily  tight  in  case  they  leak,  and  oil  squirted  on 
the  gaskets  or  around  the  spark  plugs  will  betray  leaks 
at  those  points.  The  seat  of  a  leaky  exhaust  valve  will 
be  pitted  and  burnt,  and  will  show  by  its  appearance 
that  it  seats  on  one  side  only. 

The  compression  may  become  weak  for  lack  of  suf- 
ficient lubrication.  When  this  trouble  occurs  it  is  a 
good  idea  to  pour  a  little  cylinder  oil  through  the  spark 
plug  hole,  then  see  that  the  oil  cups  are  feeding  properly. 
In  old  engines  the  compression  may  become  weak  from 
the  wear  of  the  piston  rings.  New  rings  should  then  be 
fitted,  which,  after  a  little  running,  should  wear  to  a 
good  fit  and  give  better  compression.  The  flywheel  should 
spring  back  after  being  pulled  up  against  the  compression. 

Pounding. 

\Yhen  a  pounding  noise  is  heard  the  cause  is  most 
generally  a  loose  flywheel  key.  Sometimes  pounding  is 
caused  by  early  ignition,  due  to  hot  spark  plug  or  sticking 
of  the  piston.  If  a  hot  spark  plug  is  the  cause  the  engine 
will  run  after  the  switch  is  thrown  off.  If  caused  by  a 
sticking  piston  the  latter  will  stick  tight  after  a  little 
running  under  full  load  and  stop  the  engine.  Plenty  of 
oil  fed  to  the  cylinder  will  overcome  the  sticking  of  the 
piston.  If  any  pounding  is  heard  stop  the  engine  at  once 
and  locate  the  cause  of  the  trouble  immediately,  as 
above. 

Deficient  Power. 

Occasionally,  deficient  power  in  one  cylinder  may  be 
traced  to  the  valve  spring  being  too  weak  or  too  stiff,  or 
a  broken  spring  will  cause  a  particular  cylinder  to  act 
badly.  If  the  springs  are  too  weak  the  engine  will  be 
noisy  and  weak  except  at  low  speeds. 


230  MOTOR  BOATS: 

A  possible  cause  of  deficient  power  is  small  or  crooked 
piping,  inlet  or  exhaust.  Pipe  elbows  should  never  be 
used ;  all  bends  should  be  of  easy  radius,  and  the  intake 
piping  should  be  smooth  internally. 

Gasolene  Feed. 

It  is  very  important  to  feed  the  proper  amount  of  gaso- 
lene at  all  times.  If  too  little  is  fed  base  explosions  will 
occur,  and  if  too  much  is  supplied  the  engine  will  slow 


Carbureter. — The  Watertown  Motor  Company, 
Watertown,  N.  Y. 

down.  The  best  way  to  regulate  the  gasolene  is  to  open 
up  the  throttle  wide,  put  in  the  clutch  (where  a  clutch 
is  used)  to  give  the  engine  a  full  load,  then  adjust  the 
gasolene  by  gradually  closing  it  off  until  the  highest 
speed  is  reached;  then  close  it  still  further  until  the  en- 
gine commences  to  slow  down  or  miss  fire.  Then  open- 
ing the  needle  valve  a  little  should  give  the  proper  mix- 
ture. A  little  practice  will  enable  one  to  determine  the 
proper  point  at  which  to  set  the  needle  valve,  which, 
when  once  set,  should  seldom  require  further  adjusting, 
but  it  is  well  to  try  it  occasionally  to  see  if  the  engine 
will  not  operate  on  less  gasolene. 


CONSTRUCTION  AXD  OPERATION  231 

Troubles  are  sometimes  experienced  by  not  getting 
enough  gasolene  through  the  pipes,  caused  by  the  pipes 
being  partially  stopped  up  or  the  tank  too  low,  which 
can  be  easily  remedied. 

Spark  Coil. 

The  only  delicate  part  of  the  spark  coil  is  the  contact 
points  on  the  vibrator.  These  points  are  liable  to  be- 
come burned  and  stick,  causing  misfires.  These  can  be 
examined  occasionally,  and  if  they  show  rough  surfaces 
they  can  be  smoothed  up  with  fine  emery  cloth  or  a  fine 
file.  The  vibrator  can  be  adjusted  by  the  thumb-screw 
so  it  will  give  a  good  spark.  It  is  best  to  screw  it  down 
as  far  as  possible,  but  with  weak  batteries  it  will  have 
to  be  screwed  back  to  give  less  tension  to  the  spring. 
Make-and-Break  System. 

The  procedure  in  tracing  an  ignition  fault,  says  Mr. 
Herbert  L.  Towle,  C.  E.,  will  depend  somewhat  on 
whether  the  low  tension  or  the  jump  spark  system  is 
used.  If  the  former,  the  first  step  is  to  test  the  adequacy 
of  the  spark.  Disconnect  all  the  igniters  (by  opening  the 
cut-outs,  if  there  are  any)  and  touch  one  end  of  the  wire 
from  the  coil  to  the  cylinder.  If  there  are  cut-outs,  touch 
a  screwdriver  to  the  cylinder  and  to  the  bus  bar  connect- 
ing all  the  igniters.  If  no  spark  results,  the  trouble  is  in 
the  batteries  or  in  the  wiring.  Test  the  batteries  with  an 
ammeter  or  voltmeter.  Dry  cells  should  test  5  amperes 
or  more  on  short  circuit.  Storage  cells  should  test  1.8 
volts  each  or  more,  on  open  circuit.  Never  test  storage 
cells  with  an  ammeter.  If  the  batteries  show  proper 
strength,  hunt  for  broken  wires  or  loose  connections. 
Possibly  the  wire  from  the  coil  may  be  grounded  on  the 
engine. 

Sooted  Igniters. 

If  a  good  spark  is  obtained  on  test,  it  is  still  possible 
that  the  igniters  may  be  partly  grounded  by  soot.  If  the 
igniter  plates  have  two  lava  bushings,  one  of  them  may 


232  MOTOR  BOATS: 

be  cracked,  or  soot  may  have  accumulated  in  the  air 
space  between  them.  With  mica  insulation,  soot  grad- 
ually collects  between  the  mica  leaves.  A  ground  in  any 
individual  igniter  will  have  the  effect  of  grounding  all 
the  others,  and  the  engine  will  not  run  at  all.  A  partial 
ground  due  to  soot  in  one  igniter  will  cause  missing  in 
all  the  cylinders.  To  locate  a  partial  ground,  cut  out  all 
the  igniters  except  one  and  run  the  engine  on  one  cylinder 
at  a  time  with  reduced  throttle.  If  several  igniters  are 
slightly  sooted,  missing  will  be  produced  as  though  one 
igniter  was  considerably  sooted,  but  each  cylinder  when 
running  separately  will  run  all  right.  The  only  remedy 
is  to  take  the  igniters  out  and  clean  them  thoroughly.  To 
locate  a  completely  grounded  igniter,  connect  one  igniter 
at  a  time,  taking  care  that  it  is  not  making  contact  at 
the  spark  point,  and  short  circuit  it  with  a  screwdriver. 
If  no  spark  is  produced  it  is  grounded.  Another  symptom 
will  be  a  spark  between  the  wire  to  the  coil  and  the 
igniter  binding  post  when  the  igniter  points  are  not  ma- 
king contact. 

Jump  Spark  System. 

-  If  high  tension  ignition  is  used,  first  note  by  the  sound 
of  the  engine  whether  missing  appears  to  be  confined  to 
certain  cylinders.  If  so,  the  cylinders  at  fault  are  quickly 
located  by  holding  down  with  the  fingers  the  tremblers  of 
one  or  more  of  the  spark  coils.  If  all  but  one  are  held 
down  the  'engine  will  stop,  if  the  last  cylinder  is  not 
working.  When  the  faulty  cylinder  has  been  traced, 
first  note  whether  the  trembler  gives  a  clear  buzz.  This 
can  be  done  by  opening  the  pet  cocks,  retarding  the 
spark,  and  turning  the  engine  slowly  by  hand  until  the 
desired  trembler  buzzes.  If  the  sound  is  not  clear  and 
steady,  adjust  the  contact  screw  by  turning  slightly. 
If  the  spark  is  much  feebler  than  that  given  by  the  other 
coils,  but  there  is  no  arcing  at  the  contacts  and  the 


CONSTRUCTION  AND  OPERATION  233 

trembler  is  adjusted  as  well  as  possible,  the  coil  is  prob- 
ably short  circuited  and  must  be  sent  to  the  factory. 

Sooted  Plugs. 

If  the  trembler  and  coil  are  all  right,  the  spark  plug  is 
probably  sooted.  With  some  engines  and  some  spark 
plugs,  this  is  a  very  common  occurrence,  and  the  plug 
is  the  first  thing  to  be  examined.  If  the  plug  is  clean, 
it  is  still  possible  that  the  porcelain  is  cracked  internally. 
Try  a  new  plug  or  exchange  with  the  plug  from  some 
other  cylinder.  If  the  same  cylinder  still  misses,  investi- 
gate the  cable  for  leaks  due  to  water  or  to  defective 
insulation. 

Synchronized  Ignition. 

If  "synchronized"  jump  spark  ignition  is  used — i.  e., 
a  single  coil  and  a  high  tension  distributer — the  symp- 
toms of  different  possible  troubles  will  be -substantially 
as  above,  with  the  exception  that  local  misfiring  can  only 
be  due  to  leakage  in  the  spark  plugs  or  spark  plug  cables, 
or  to  defective  insulation  in  the  distributer  itself.  The 
latter  may  be  due  to  water  or  dirt  or  to  metal  particles, 
and  should  not  appear  if  the  distributer  is  kept  clean. 
The  trembler  for  such  a  system  does  duty  for  all  the 
cylinders  instead  of  only  one,  and  its  contact  points 
therefore  require  frequent  attention. 

Sudden  Stoppage. 

If  the  engine  stops  suddenly -without  warning,  the 
cause  is  probably  a  broken  battery  wire.  If  it  gives  a 
few  weak  explosions  before  stopping,  the  cause  may  be 
a  suddenly  slipped  timer,  or  the  gasolene  may  have 
given  out.  Water  in  the  gasolene  will  stop  the  engine 
very  abruptly,  but  there  are  usually  a  few  spasmodic 
explosions  before  it  ceases  entirely.  If  the  explosions 
grow  weaker  for  some  moments  before  the  engine  stops, 
and  if  on  priming  the  carbureter  and  cranking,  the  engine 
starts  again  but  presently  stops,  the  flow  of  gasolene  to 


234  MOTOR  BOATS: 

the  carbureter  is  probably  obstructed  by  dirt  or  fluff, 
which  may  be  in  the  gasolene  pipe,  in  the  carbureter 
intake,  or  in  the  gasolene  filter  (if  the  carbureter  has 
one).  See  if  the  gasolene  runs  down  freely  when  the 
float  is  depressed.  If  it  does  not,  disconnect  the  gaso- 
lene pipe  at  the  carbureter.  Most  carbureters  have  a 
draining  connection  or  petcock,  where  the  gasolene  enters, 
and  by  opening  this,  the  accumulated  dirt  or  water  may 
be  flushed  out. 

Preignition. 

Occasionally,  the  explosions  in  one  or  more  cylinders 
will  produce  a  sharp  metallic  knocking  quite  unlike  the 
muffled  thump  due  to  loose  bearings.  This  noise  is  due 
to  spontaneous  ignition  of  the  charge  before  the  spark 
occurs,  and  is  caused  usually  by  incandescent  particles 
of  carbon  on  the  piston  head.  This  carbon  accumulates 
gradually  as  a  residue  of  the  cylinder  oil  and  requires  to 
be  scraped  out  once  or  twice  in  a  season. 

Dirt  in  the  Carbureter. 

When  you  have  tried  all  other  things  and  failed  to 
remedy  the  trouble,  look  for  obstructions  or  dirt  in  the 
carbureter  or  gasolene  pipe.  Do  not  say,  "Oh,  I  know 
they  are  all  right,"  for  you  do  not  know  until  you  ex- 
amine them.  A  piece  of  waste,  cork,  chip,  dirt,  accumu- 
lations of  paraffin  or  glue  from  gasolene  barrels  may 
work  through  the  pipe  connected  to  the  carbureter,  and 
while  not  stopping  the  entire  supply  will  often  cut  down 
the  supply,  causing  slowing  down  and  back-firing,  often 
stopping  the  engine,  gradually  filtering  through  and  al- 
lowing the  engine  to  start,  but  later  giving  the  same 
trouble. 

Test  for  Preignition. 

On  throwing  off  the  switch,  if  engine  continues  to  run 
the  cause  is  preignition. 


CONSTRUCTION  AND  OPERATION  235 

Removing  Carbon. 

Avoid  trouble  by  using  a  good  grade  of  gas  engine 
cylinder  oil.  A  good  plan  is  to  put  about  two  or  three 
tablespoonfuls  of  turpentine  in  each  cylinder,  and  run  the 
engine  the  same  as  you  would  when  using  kerosene  to 
clean  out  the  carbonization  on  piston  cylinder  and 
rings ;  do  it  after  running,  say,  200  miles  or  more,  or  at 
any  time  cylinders  have  heated  or  become  carbonized. 
Kerosene  is  mostly  used  to  clean  out  cylinder;  either 
kerosene  or  turpentine  will  do. 

Flooding  Carbureter. 

Flooding  at  the  carbureter  may  be  caused  by  dirt  under 
the  needle  valve  and  sometimes  can  be  removed  by 
jarring  the  carbureter  or  pressing  the  float  spindle  against 
its  seat  and  revolving,  otherwise  it  will  be  necessary  to 
remove  the  cover  on  the  float  chamber  and  lift  the  float 
out;  the  needle  valve  can  then  be  inserted  and  moved 
around  on  its  seat,  thus  removing  the  dirt.  Be  sure  that 
the  carbureter  stands  plumb. 

A  carbureter  which  drips  continually  when  the  engine 
is  not  running  is  hard  to  start,  owing  to  over-richness 
of  the  mixture,  especially  if  the  engine  has  been  shut 
down  for  a  few  minutes  without  closing  the  gasolene 
valve.  If  the  gasolene  level  is  more  than  1/16  or  l/%  inch 
below  the  spray  orifice  it  will  not  be  as  easy  as  it  should 
be  to  run  the  engine  slowly. 

Carbureter  Adjustment. 

Irregular  explosions  may  be  caused  from  either  im- 
proper mixture,  or  defective  spark.  The  mixture  can  be 
adjusted  by  the  needle  valve  at  the  bottom  of  carbureter. 
If  the  gasolene  is  turned  off  too  much  it  may  cause  back 
firing,  or  base  explosions,  and  therefore  must  be  opened 
up  again  slightly.  This  rule  should  be  borne  well  in 
mind.  After  the  carbureter  is  properly  adjusted  it  seldom 
requires  any  changing.  Any  defect  in  spark  will  be 
located  in  the  coil,  plug,  battery,  or  timing  mechanism. 


236  MOTOR  BOATS: 

TROUBLE  HINTS  AND  TIPS. 

Over-Stiff  Vibrator. — An  over-stiff  vibration  spring  re- 
quires considerable  current  to  make  it  work,  and  will 
cause  misfiring  before  the  batteries  are  spent. 

Weak  Battery. — A  weak  or  worn  out  battery  will  cause 
irregular  explosions  and  should  be  renewed.  When-  test- 
ing a  battery  of  dry  cells  use  an  ammeter,  as  it  will  show 
the  condition  of  the  cells  much  better  than  a  voltmeter. 

Misfiring. — An  engine  misfiring  or  exploding  irregu- 
larly will  sometimes  cause  a  novice  to  think  that  some 
of  the  internal  mechanism  has  become  loose  and  is  strik- 
ing against  some  part  of  the  cylinder,  whereas  the  knock- 
ing or  hammering  noise  is  simply  the  result  of  the  un- 
steady motion  of  the  moving  parts. 

If  the  missing  affects  all  the  cylinders  alike,  it  may 
be  due  to  a  weak  battery,  or  to  a  loose  connection  or 
broken  wire  anywhere  between  the  battery  and  the  coil 
or  between  the  battery  and  the  ground  connection  on  the 
engine.  A  loose  connection  may  touch  and  break  contact 
from  vibration  as  the  engine  runs.  If  the  missing  is 
most  pronounced  at  high  speed,  it  is  likely  to  be  due  to 
rough  contacts  in  the  timer  if  the  latter  is  of  the  roller 
type.  Irregular  firing,  with  or  without  actual  missing, 
may  be  due  to  the  use  of  grease  instead  of  oil  in  a  roller 
contact  timer,  or  to  the  body  of  the  timer  wabbling  on 
its  bearing  from  wear,  or  to  lost  motion  in  the  connections 
operating  the  spark  advance. 

Irregular  Missing. — Irregular  missing  may  be  caused 
by  a  dirty  spark  plug,  a  sticking  coil  vibrator,  or  wrong 
adjustment  of  vibrator,  platinum  points  on  vibrator  or 
spark  coil  pitted  or  burned  off,  dirty  or  loose  in  the 
spring,  bad  commutator  or  ground ;  if  irregular  knocking 
also  occurs,  it  may  be  a  loose  primary  wire.  Sometimes 
.  the  jump  spark  wire  has  the  insulation  worn  off  or  is 
poorly  insulated,  and  the  current  jumps  outside  the  cyl- 


CONSTRUCTION  AND  OPERATION  237 

inder.  Primary  wire  (the  small  wire)  may  be  broken 
inside  the  insulation,  or  may  have  dirty  connection,  or 
may  be  worn  through *and  only  a  few  strands  holding1. 

Cracked  insulation  on  either  porcelain  or  mica  spark 
plugs  will  give  trouble. 

\Yhen  a  good  spark  is  had  at  the  coil  and  none  or  a 
weak  spark  from  the  end  of  the  secondary  wire,  there  is 
a  leak  in  the  secondary  wire. 

If  a  good  spark  is  obtained  at  the  end  of  the  secondary 
wire  and  none  or  a  poor  spark  at  the  spark  plug,  the 
point  or  points  need  adjusting  or  the  plug  is  short- 
circuited. 

Back  Firing. — The  principal  cause  is  delayed  com- 
bustion of  previous  charge.  When  the  mixture  enters 
the  cylinder  and  does  not  contain  sufficient  gasolene, 
it  makes  a  low  mixture,  so  slow  in  combustion  that  it 
continues  to  burn  on  both  the  working  and  exhaust 
strokes  of  the  piston,  the  flame  remaining  in  the  cylinder 
long  enough  to  fire  the  incoming  fresh  charge,  which 
escapes  back  through  the  receiving  pipe. 

Remember,  in  case  of  weak  mixture,  feed  a  little  more 
gasolene.  If  this  does  not  control  it,  look  for  carbon  de- 
posits and  remove  them. 

Weak  Mixture. — Weak  mixture  or  late  explosions 
cause  slowr  burning ;  delayed  flame  in  cylinder,  when  inlet 
port  from  the  by-pass  is  uncovered  by  the  piston,  causes 
crank  case  explosions  or  back-fire.  When  engine  back- 
fires into  the  carbureter  it  is  usually  a  sign  that  you  are 
not  getting  enough  gasolene.  Throttling  the  carbureter 
too  much  often  causes  back-firing,  which  may  be  over- 
come when  engine  is  running  at  full  speed  by  feeding 
more  gasolene  and  advancing  the  spark. 

Back-firing  may  be  caused  by  running  with  the  throttle 
of  carbureter  wide  open  and  spark  level  retarded  too 
much.  If  that  is  not  the  trouble,  open  the  needle  valve 
a  little  at  a  time,  until  it  explodes  regularly. 


238  MOTOR  BOATS: 

Preignition. — Caused  by  sparking  too  soon,  over-heated 
cylinders,  over-advanced  timer,  over-heated  projections 
or  deposits  of  burnt  carbon  in  cylinder  or  igniting  cham- 
ber, producing  a  deep,  heavy  pound.  If  this  is  the 
cause,  the  pounding  will  cease  as  soon  as  the  deposits 
are  removed,  or  the  spark  made  later.  Always  try  chan- 
ging time  of  spark  before  tinkering  with  the  inside  of 
the  cylinder. 

Tight  Bearings. — A  tight  bearing  occurs  frequently  in 
an  engine  which  turned  easily  before  installing.  The 
cause  for  hard  turning  over  is  from  springing  the  base  of 
engine  in  screwing  down  on  an  uneven  engine  bed,  throw- 
ing the  crankshaft  bearings  out  of  line.  To  prove  this, 
loosen  the  leg  screw  and  turn  flywheel  over. 

Temperature  of  Gasolene. — If  a  dish  of  gasolene  is  set 
out  where  temperature  is  at  zero  it  will  not  evaporate. 
This  should  explain  why  it  is  often  hard  to  start  in  cold 
weather. 

Short  Circuit. — If  the  wires  connecting  the  batteries 
are  carelessly  attached  so  as  to  come  in  contact  with 
zinc  and  carbon,  short  circuit  will  be  the  result  if  insula- 
tion is  worn,  or  the  zincs  come  together. 

Testing  Spark  Plug. — To  test  the  jump  spark  plug  for 
fouling,  injury  or  short  circuit  in  plug,  remove  the  plug 
from  cylinders,  lay  it  on  a  clean  metallic  part  of  the  en- 
gine, usually  on  top  of  cylinder,  with  wires  attached  to 
the  plug,  being  careful  that  only  the  outside  metal  of  the 
plug  containing  the  tread  comes  in  contact  with  the  en- 
gine, the  same  as  if  placed  in  the  cylinder.  Turn  over 
the  flywheel  until  contact  is  made  at  the  commutator  or 
timer.  If  the  vibrator  of  the  spark  coil  does  not  buzz, 
adjust  by  thumbscrew  until  it  works.  If  it  does  not  work, 
clean  the  points  between  the  thumbscrew  adjuster  and 
vibrator.  When  vibrator  works,  notice  the  size  of  spark 
at  the  points  of  plug. 


CONSTRUCTION  AND  OPERATION  239 

If  the  spark  jumps  the  space  between  points  the  plug 
is  all  right.  If  not  a  good  spark,  try  opening  or  closing 
the  space  a  little. 

Do  not  put  your  hands  on  plug  when  contact  is  on. 
You  will  be  apt  to  get  an  unpleasant  though  not  danger- 
ous shock. 

Valve  Timing. — The  exhaust  valve  of  a  four-cycle  en- 
gine should  open  when  the  crank  lacks  about  40  degrees 
of  its  bottom  position,  and  should  close  just  after  the 
crank  has  reached  its  top  position.  The  inlet  valve  should 
open  approximately  when  the  exhaust  valve  closes,  and 
should  stay  open  until  the  crank  is  about  20  degrees  be- 
yond its  bottom  position.  If  the  valves  are  wrongly 
timed  the  cause  may  be  found  in  slipping  of  the  valve 
cams  on  theii  shaft,  or  in  wear  of  the  cams  or  the  valve 
lifters.  There  should  be  at  least  1/32  inch  clearance 
under  the  valve  stems  when  the  valves  are  shut.  After 
an  engine  has  been  overhauled,  the  gears  may  be  in- 
correctly assembled,  so  that  all  the  valves  open  and  close 
later  or  earlier  than  they  should.  Usually  the  gear  teeth 
are  marked  with  a  prick  punch  to  show  the  correct 
setting. 

A  FEW  HINTS  FOR  ALL. 

Do  not  attempt  to  fill  a  gasolene  tank  at  night,  unless 
an  electric  hand-light  is  used  for  illumination ;  the  use 
of  a  light  or  lantern  is  only  tempting  danger. 

Make  a  landing  heading  into  the  wind  or  against  the 
current. 

It  is  a  good  idea  to  always  carry  recharges  for  your 
battery  or  else  a  set  of  dry  cells ;  better  still  is  a  magneto. 

Before  you  start  your  motor  in  the  spring,  clean  it 
thoroughly,  removing  all  the  old  grease,  and  see  that 
everything  is  in  perfect  order,  free  from  rust.  Pour  a 
small  cupful  of  kerosene  in  the  cylinder  through  the 
priming  cup.  Turn  the  engine  over  a  dozen  times  and 
then  let  it  stand  overnight.  This  will  loosen  the  piston 


240  MOTOR  BOATS: 

rings,  if  they  have  stuck,  and  greatly  increase  the 
compression. 

In  screwing  down  compression  grease  cups,  do  so 
while  the  motor  is  running,  otherwise  the  lubricant  will 
not  enter  the  grease  duct. 

When  you  hear  an  unusual  noise  about  your  motor,  do 
not  keep  on  running.  Something  is  wrong  and  requires 
attention.  The  old  adage  that  "a  stitch  in  time  saves 
nine,"  well  applies  here.  Stop  and  find  out  the  cause  and 
then  remedy  the  fault,  if  possible. 

There  may  be  a  number  of  reasons  for  the  pounding 
in  a  motor — lack  of  lubrication,  lack  of  water  supply, 
spark  advanced  too  far,  too  much  gasolene,  or  the  fly- 
wheel key  loose.  Drive  in  the  flywheel  key  first ;  if  this 
does  not  remedy  the  trouble,  see  that  the  pump  is  work- 
ing; if  the  pounding  continues,  look  to  your  lubrication, 
and  finally  see  that  the  spark  is  not  advanced  too  much. 
Sometimes,  however,  through  the  use  of  poor  cylinder 
oil,  the  rings  on  the  piston  will  become  gummed  and 
stick,  thus  causing  a  pound.  In  this  case  a  little  kero- 
sene poured  into  the  cylinder  through  the  priming  cup 
and  the  motor  turned  over  several  times  will  loosen  the 
rings. 

When  your  motor  doesn't  start  on  one  or  two  turns  of 
the  crank,  it  is  time  to  look  around  and  see  what  you 
have  forgotten — something,  nine  times  out  of  ten.  Thus, 
the  Camden  Anchor-Rockland  Machine  Co.,  of  Camden, 
Maine,  tell  of  a  case  where  they  sent  a  man  400  miles 
to  put  a  customer  right,  and  found  that  he  had  forgotten 
it  was  necessary  to  put  in  his  switch — and  he  had  been 
operating  the  boat  a  month  at  that. 

It  sometimes  happens  that  a  cylinder  gasket  becomes 
destroyed  in  removing  the  head  of  a  motor,  and  that  new 
packing  is  almost  impossible  to  obtain.  In  such  cases 
heavy  manila  paper  saturated  with  shellac,  will  act  very 
well.  Thin  copper,  if  obtainable,  is  still  better.  Asbestos 


CONSTRUCTION  AND  OPERATION  241 

is  commonly  used  and  is  usually  found  where  there  is  an 
engine.  It  is  well  to  soak  asbestos  in  linseed  oil  before 
using,  and  after  the  motor  is  run  awhile  the  head  nuts 
should  be  tightened. 

Poor  lubricating  oil  has  been  the  cause  of  a  good  deal 
of  trouble  with  gasolene  motors.  We  have  heard  of  a 
number  of  cases  where  oil  men  laid  claim  to  having  the 
best  thing  on  earth,  and  the  result  has  been  that  if  this 
was  purchased  trouble  occurred.  There  are  good  brands 
of  oil  in  the  market  and  it  will  pay  to  use  the  best. 


Knox  4-cycle,  4-cylinder  Engine,  40  H.  P. 


When  you  have  trouble  with  your  motor,  don't  do  like 
the  embryo  hunter  who  was  lost  in  the  woods  and  ran 
around  in  a  circle,  hoping  to  find  his  way  out.  Follow  one 
line  to  the  end,  and  if  you  do  not  locate  the  trouble  there, 
go  to  the  next.  This  generally  proves  the  shortest  way 
out  of  the  woods. 

Every  owner  of  a  motor-boat  should  be  equipped  with 
an  ammeter  (ampere  meter)  for  the  purpose  of  testing 
batteries.  There  are  voltmeters  also,  but  these  are  use- 
less ;  it  is  the  amperage  that  runs  down,  not  the  voltage. 
The  voltage  is  the  pressure  of  current  and  the  amperage 
is  the  quantity.  The  voltage  may  be  sufficient  when 
there  is  no  amperage,  and  the  result  is  that  the  charge 

16 


242  MOTOR  BOATS: 

of  gas  will  not  ignite.  It  is  well  to  remember  also  that  a 
spark  apparently  good  in  the  open  air  is  not  so  strong  in 
the  cylinder  when  under  compression.  This  often  mis- 
leads the  unaccustomed  in  such  matters.  A  spark  suf- 
ficient to  ignite  gas  must  be  of  a  blue  or  purple  hue,  which 
indicates  its  quality.  A  purely  red  spark  is  apt  to  be 
weak. 

To  store  a  motor  away  for  the  season,  clean  it  thor- 
oughly. See  that  all  water  is  drained  out  of  water  jacket 
and  pipes.  See  that  the  check  valves  are  clear.  Take 
out  igniter,  oil  it  with  heavy  oil  and  place  it  away  where 
it  will  not  rust.  Pour  about  a  cupful  of  cylinder  oil  into 
the  cylinder  through  igniter  hole,  turn  the  engine  over 
until  the  oil  is  well  distributed  over  the  inside  of  engine, 
oil  all  bearings  with  heavy  oil,  and  grease  thoroughly. 
Cover  all  parts  exposed  to  the  air,  that  will  rust,  with 
heavy  oil  mixed  with  tallow.  Unpack  pump  and  place 
motor,  well  covered  up,  in  a  dry  place,  free  from  dirt 
and  rust. 


A  Ferro  Motor  Boxed  for  Shipment. 


CHAPTER  XXI 
DON'TS  FOR  MOTOR  BOATMEN. 

Don't  fill  gasolene  tank  by  artificial  light. 

Don't  put  gasolene  in  tank  without  straining. 

Don't  try  to  run  engine  without  gasolene  in  tank. 

Don't  try  to  start  the  engine  with  gasolene  valve 
closed. 

Don't  try  to  start  engine  with  worn  out  batteries. 

Don't  try  to  run  engine  with  soot  fouled  spark  plugs. 

Don't  go  without  tools  in  the  boat. 

Don't  cast  off  until  engine  is  started. 

Don't  start  without  lubricating  oil. 

Don't  neglect  opening  lubricators. 

Don't  allow  base  of  motor  to  get  out  of  oil. 

Don't  put  too  much  oil  in  base. 

Don't  fail  to  observe  if  water  pump  works. 

Don't  neglect  to  oil  clutch. 

Don't  adjust  clutch  unless  it  needs  it. 

Don't  let  batteries  get  wet. 

Don't  let  wires  run  through  bilge  water. 

Don't  let  wire  connections  get  loose. 

Don't  stop  motor  until  boat  reaches  mooring. 

Don't  stop  motor  and  leave  charging  switch  in  contact. 

Don't  forget  to  close  lubricator  and  gasolene  valves 
when  motor  is  stopped. 

Don't  hesitate  to  write  or  ask  for  needed  information. 

Don't  use  lighted  match  to  examine  contents  of  gaso- 
lene tank. 

Don't  pack  stern  stuffing  box  with  asbestos. 

Don't  let  bare  wires  come  in  contact  with  the  motor. 

Don't  let  wire  connections  and  terminals  get  loose. 


244  MOTOR  BOATS: 

Don't  blame  the  manufacturer  or  the  motor  for  every 
little  thing  that  happens. 

Don't  forget  that  you  are  a  factor  in  the  successful 
running  of  the  motor.  r 

Don't  get  nervous  or  excited — sit  down  and  think  a 
minute. 

Don't  forget  that  the  builders  are  as  much  interested 
in  the  performance  of  the  motor  as  you  are. 

Don't  forget  that  eighty-five  per  cent  of  motor  fail- 
ure can  be  traced  to  electric  trouble ;  either  in  the  battery 
or  the  coil  or  the  wiring  or  the  plugs. 

Don't  try  to  start  the  motor  with  any  "lead"  on. 

Don't  run  at  too  high  speed  just  to  show  off,  as  you 
might  burn  out  bearings. 

Don't  fool  with  adjustment  of  spark  coil.  The  vibra- 
tor is  properly  adjusted  at  factory  and  seldom  needs 
readjustment. 

Don't  take  engine  apart  unless  absolutely  necessary 
and  if  you  have  to  do  so  to  get  at  inside  of  crank-case, 
simply  tip  cylinder  over,  not  removing  piston. 

Don't  expect  to  get  best  results  from  an  engine  work- 
ing on  a  shaky  foundation. 

Don't  forget  to  turn  down  grease  cups  every  hour  or 
so,  forcing  grease  upon  your  bearings.  Be  sure  there  is 
plenty  of  grease  in  the  cups. 

Don't  forget  that  extra  can  of  oil  if  you  are  going  on 
a  long  trip. 

Don't  try  to  start  engine  with  the  draining  plug  out 
of  the  bottom  of  crank-case  or  with  drain  cock  open. 

Don't  try  to  use  batteries  after  they  are  played  out ;  it 
is  a  good  plan  to  purchase  an  extra  set  of  batteries  after 
the  ones  you  are  using  have  been  in  service  about  two 
months.  We  have  seen  batteries  that  will  run  for  six 
months  and  still  be  in  good  condition ;  but  we  have  also 
seen  them  played  out  in  a  few  weeks. 


CONSTRUCTION  AND  OPERATION  245 

Don't  forget  to  open  sea-cock  to  pump,  if  you  have 
one. 

Don't  try  to  start  without  first  making  sure  that  the 
spark  lever,  timer  or  commutator  is  retarded. 

Don't  try  to  start  without  the  switch  turned  on. 

Don't  try  to  start  an  engine  which  has  a  reverse  gear 
or  clutch,  without  making  sure  the  lever  is  set  neutral. 

Don't  screw  the  spark  plug  in  too  tightly  but  only  just 
enough  to  prevent  leakage  and  hold  firmly.  You  may 
want  to  take  it  out  again. 

Don't  put  your  wrench  on  upper  nut  on  spark  plug 
when  plug  is  in  cylinder.  You  may  destroy  it. 

Don't  use  other  than  the  best  gas  engine  oil.  The  best 
steam  engine  oil  will  not  do. 

Don't  think  that  because  too  much  oil  is  bad  that  too 
little  is  better. 

Don't  forget  to  throw  out  the  switch  or  pull  the  button, 
and  put  in  your  pocket  when  not  running. 

Don't  run  engine  unless  the  pump  is  working. 

Don't  expect  engine  to  run  if  wire  connections  get 
loose,  batteries  weak,  spark  plug  dirty  or  wire  poorly 
insulated. 

Don't  put  your  face  close  to  an  opening  in  gas  engine 
when  switch  is  on,  or  to  see  the  spark  take  place. 

Don't  run  an  engine  if  a  hammering  or  knocking  noise 
is  heard ;  find  the  trouble. 

Don't  forget  to  turn  on  gasolene  cocks  both  at  tank 
and  engine  before  starting. 

Don't  think  it  waste  of  time  to  clean  off  ignition  points 
occasionally. 

Don't  wear  yourself  out  cranking  an  engine ;  if  it  does 
not  start  after  three  or  four  turns  after  priming  some- 
thing is  wrong. 

Don't  think  that  a  thump,  pound  or  thud  about  your 
engine  is  always  due  to  some  trouble  in  the  cylinder  or 
connecting  rod. 


246  MOTOR  BOATS: 

Don't  put  a  check  valve  between  carbureter  or  vapor- 
izer on  a  three-port  engine. 

Don't  use  90-degree  els,  when  possible  to  use  two 
45-degree,  especially  on  exhaust  pipe. 

Don't  forget  that  a  union  on  each  pipe  as  near  to  end 
as  possible  is  good  practice. 

Don't  try  to  start  with  carbureter  throttle  entirely 
closed  or  entirely  open. 

Don't  adjust  the  carbureter  as  soon  as  the  engine  works 
badly;  it  may  be  poor  ignition,  poorly  seated  valves, 
poor  water  circulation,  etc. 

Don't  expect  gasolene  to  run  up-hill. 

Don't  expect  an  engine  installed  below  the  water  line 
with  underwater  exhaust  to  run,  unless  the  exhaust  pipe 
is  carried  above  the  water  line,  before  entering  the  water 
line,  and  an  air  valve  or  relief  cock  placed  at  highest 
point. 

Don't  think  a  dirty,  rusty  engine  will  run  as  well  or 
last  as  long  as  a  well-kept  one. 

Don't  forget  that  success  or  failure  depends  upon 
yourself. 

•  Don't  forget  to  turn  off  the  gasolene  cock  when  not 
running. 

Don't  forget  to  fill  gasolene  tank. 

Don't  forget  to  draw  water  out  of  cylinder  in  cold 
weather. 

Don't  wipe  engine  while  running. 

Don't  use  too  much  gasolene ;  more  power  is  developed 
with  smokeless  mixture. 

Don't  pile  anything  on  batteries. 

Don't  be  afraid  to  fix  your  engine. 

Don't  get  excited,  but  go  carefully. 

Don't  trust  wire  screen  strainer,  but  use  chamois  skin, 
and  save  trouble.  If  chamois  skin  is  not  handy,  use 
handkerchief. 


CONSTRUCTION  AND  OPERATION 


247 


Don't  look  for  the  opening  in  your  gasolene  tank  or  a 
leak  with  a  match. 

Don't  reduce  the  size  of  pipe  after  leaving  the  engine. 

Don't  have  any  more  turns  in  exhaust  pipe  than 
possible. 

Don't  see  how  close  you  can  run  to  another  boat. 

Don't  cut  in  ahead  of  a  ferry  boat  or  any  other  boat 
just  because  you  have  the  right  of  way.  They  may  not 
respect  any  rule  except  the  rule  of  might. 

Don't  forget  that  all  sail  craft,  big  or  sjnall,  have  right 
of  way  over  power  craft. 

Don't  forget  to  offer  assistance  to  a  boat  in  distress, 
and  always  ask  it  or  accept  it  when  offered  when  in 
distress  yourself. 


A  Pacific  Coast  Type  of  Launch. 


CHAPTER  XXII 

RULES  OF  NAVIGATION. 

The  following  rules  and  regulations  for  steam  vessels 
apply  also  to  the  navigation  of  the  Xaphtha  or  Gasolene 
Launch,  and  should  be  followed  to  prevent  collisions: 

Lights. 

The  lights  mentioned,  and  no  others,  should  be  car- 
ried in  all  weathers  between  sunset  and  sunrise: 

(A)  At  the  bow,  a  bright  white  light,  of  such  a  char- 
acter as  to  be  visible  on  a  dark  night.with  a  clear  atmos- 
phere, and  so  constructed  as  to  show  a  uniform  and  un- 
broken light  over  an  arc  of  the  horizon  of  twenty  points 
of  the  compass,  and  so  fixed  as  to  throw  the  light  ten 
points  on   each   side   of  the  vessel,  namely,   from   right 
ahead  to  two  points  abaft  the  beam  on  either  side. 

(B)  On  the  starboard  side,  a  green  light  of  such  a 
character  as  to  be  visible  on  a  dark  night,  with  a  clear 
atmosphere,  and  so  constructed  as  to  show  a  uniform 
and  unbroken  light  over  an  arc  of  the  horizon  of  ten 
points  of  the  compass,  and  so  fixed  as  to  throw  the  light 
from  right  ahead  to  two  points  abaft  the  beam  on  the 
starboard  side. 

(C)  On  the  port  side,  a  red  light  of  such  a  character 
as  to  be  visible  on  a  dark  night,  with  a  clear  atmosphere, 
and  so  constructed  as  to  show  a  uniform  and  unbroken 
light  over  an  arc  of  the  horizon  of  ten  points  of  the  com- 
pass, and  so  fixed  as  to  throw  the  light  from  right  ahead 
to  two  points  abaft  the  beam  on  the  port  side. 

The  green  and  red  lights  should  be  fitted  with  inboard 
screens. 


250 


MOTOR  BOATS: 


Diagrams. 

The  following  diagrams  are  intended  to  illustrate  the 
working  of  the  foregoing  system  of  colored  lights : 
First  Situation. 

Here  the  two  colored  lights  visible  to  each,  will  indicate 
their  direct  approach    ("head  and   head")   toward  each 


other.  In  this  situation  it  is  a  standing  rule  that  both 
shall  put  their  helms  to  port  and  pass  to  the  right,  each 
having  previously  given  one  blast  of  the  whistle. 

Second  Situation. 

Here  the  green  light  only  will  be  visible  to  each,  the 
screens  preventing  the  red  light  from  being  seen.     They 


are  therefore  passing  to  starboard,  which  is  rulable  in 
this  situation,  each  pilot  having  previously  signified  his 
intention  by  two  blasts  of  the  whistle. 

Third  Situation. 

A  and  B  will  see  each  other's  red  light  only,  the  screens 
preventing  the  green  lights  from  being  seen.     Both  ves- 


sels are  evidently  passing  to  port,  which  is  rulable  in 
this  situation,  each  pilot  having  previously  signified  his 
intention  by  one  blast  of  the  whistle. 

Fourth  Situation. 

This   is   a   situation   requiring  great  caution;  the  red 
light  of  B  in  view  to  A,  and  the  green  light  of  A  in  view. 


CONSTRUCTION  AND  OPERATION  251 

to  B,  will  inform  both  that  they  are  approaching  each 
other  in  an  oblique  direction.  A  should  put  his  helm  to 
port,  and  pass  astern  of  B,  while  B  should  continue  on 


his  course  or  port  his  helm,  if  necessary  to  avoid  col- 
lision, each  having  previously  given  one  blast  of  the 
whistle,  as  required  when  passing  to  the  right. 

Fifth  Situation. 

This  is  a  situation  requiring  great  caution;  the  red 
light  of  A  in  view  to  B,  and  the  green  light  of  B  in  view 
to  A,  will  inform  both  that  they  are  approaching  each 
other  in  an  oblique  direction.  B  should  put  his  helm 


to  port,  and  pass  astern  of  A,  while  A  should  continue  on 
his  course  or  port  his  helm,  if  necessary  to  avoid  colli- 
sion, each  having  previously  given  one  blast  of  the 
whistle,  as  required  when  passing  to  the  right. 

Sixth  Situation. 

In  this  situation  A  will  only  see  the  red  light  of  B  in 
whichever  of  the  three  positions  the  latter  may  happen 
to  be,  because  the  green  light  will  be  hid  from  view; 
A  will  be  assured  that  the  port  side  of  B  is  toward  him, 
and  that  the  latter  is  therefore  crossing  the  bows  of  A 
in  some  direction  to  port ;  A  will  therefore  (if  so  near  as 


252 


MOTOR  BOATS: 


to  fear  collision)  port  his  helm  with  confidence/ and 
pass  clear.  On  the  other  hand,  B,  in  either  of  the  three 
positions,  will  see  both  the  red  and  green  lights  of  A, 


by  which  the  former  will  know  that  A  is  approaching 
directly  toward  him ;  B  will  act  accordingly  and  keep 
away  if  necessary. 

Seventh  Situation. 

In  this  situation  A  will  only  see  the  green  light  of  B 
in  whichever  of  the  three  positions  the  latter  may  hap- 
pen to  be,  because  the  red  light  will  be  hid  from  view; 
A  will  be  assured  that  the  starboard  side  of  B  is  toward 
him,  and  that  the  latter  is  therefore  crossing  the  bows 
of  A  in  some  direction  to  starboard;  A  will  therefore  (if 
so  near  as  to  fear  collision)  starboard  his  helm  with 


confidence  and  pass  clear.  On  the  other  hand,  B,  in 
either  of  the  three  positions,  will  see  both  the  red  and 
green  lights  of  A,  by  which  B  will  know  that  A  is  ap- 
proaching directly  toward  him;  B  will  act  accordingly, 
and  keep  away  if  necessary. 

The   manner   of   fixing   the   colored   lights   should   be 
particularly  attended  to.     They  will  require  to  be  fitted 


CONSTRUCTION  AND  OPERATION  253 

each  with  a  screen,  of  wood  or  canvas,  on  the  inboard 
side,  and  close  to  the  light,  in  order  to  prevent  both 
being  seen  at  the  same  moment  from  any  direction  but 
that  right  ahead  to  two  points  abaft  the  beam. 

This  is  important,  for  without  the  screens  any  plan  of 
bow  lights  would  be  ineffectual  as  a  means  of  indicating 
the  direction  of  steering.  This  will  be  readily  understood 
by  a  reference  to  the  preceding  illustrations,  where  it 
will  appear  evident  that  in  any  situation  in  which  two 
vessels  may  approach  each  other  in  the  dark  the  colored 
lights  will  instantly  indicate  to  both  the  relative  course 
of  each ;  that  is,  each  will  know  whether  the  other  is  ap- 
proaching directly  or  crossing  the  bows  either  to  star- 
board or  port. 

This  intimation,  with  the  signals  by  whistle,  as  pro- 
vided, is  all  that  is  required  to  enable  vessels  to  pass 
each  other  in  the  darkest  night  with  almost  equal  safety 
as  in  broad  day.  If  at  anchor,  all  vessels,  without  dis- 
tinction, must  exhibit  a  bright  white  light  as  far  as  pos- 
sible above  the  surface  of  the  water. 

The  lights  carried  by  sailing  vessels  are  the  same  as 
those  given,  except  the  white  light. 

Vessels  under  power  are  always  required  to  give  way 
to  those  under  sail. 

Alter  course  to  starboard  and  pass  on  port  side  of 
other  vessel  when  meeting  end  on  or  nearly  so.  Follow 
this  rule  at  night  whenever  both  side  lights  of  approach- 
ing vessel  are  visible  across  the  beam. 

When  crossing,  the  vessel  having  the  other  on  her 
starboard  side,  must  not  obstruct  the  other's  passage. 

A  power  vessel  shall  not  obstruct  the  passage  of  a 
sailing  vessel. 

,  Do  not  overtake  and  pass  another  vessel  in  a  narrow 
passage. 

The  whistle  signals  indicating  the  course  required  are 
specified. 


254  MOTOR  BOATS: 

When  a  signal  is  received,  answer  with  the  same 
signal. 

One  blast  signifies,  "I  am  directing  my  course  to  star- 
board" (right). 

Two  blasts  signify,  "I  am  directing  my  course  to  port" 
(left). 

Three  blasts  signify,  "My  engines  are  full  speed 
astern." 

When  nearing  a  bend  in  the  channel  sound  one  long 
blast. 

Give  whistle  signals  by  day  or  night  only  when  other 
vessel  signaled  is  in  sight: 

Fog  signals  only  are  given  in  thick  foggy  weather. 

Upon  being  overtaken  by  another  vessel,  a  white  light 
must  be  shown  astern,  visible  over  twelve  points  of  the 
compass  aft. 

Rules  regarding  sidelights  are  to  be  complied  with 
when  vessel  is  under  way  and  not  otherwise. 

A  white  light  is  to  be  shown  while  at  anchor,  visible 
all  around  the  horizon. 

A  whistle,  siren,  fog-horn  or  something  of  similar 
nature  is  to  be  used  as  a  fog  signal.  A  "prolonged  blast" 
is  from  four  to  six  seconds'  duration. 

One  prolonged  blast  at  one-minute  intervals  or  less 
must  be  given  when  the  boat  has  way  upon  her. 

In  sailing  vessels,  one  blast  at  one-minute  intervals  or 
less  must  be  given  when  on  starboard  tack ;  two  blasts  at 
one-minute  intervals  when  on  port  tack :  with  wind  abaft 
the  beam,  three  blasts  at  similar  intervals. 


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